Slipstream space

Slipstream space, colloquially known as slipspace, or the Slipstream and formally known as Shaw-Fujikawa space or subspace by the United Nations Space Command, is a dimensional subdomain of alternate spacetime consisting of eleven non-visible infinitesimal dimensions used for faster-than-light travel. Making a transition from one place to another via slipspace is known as a "slip", or "jump". A device which allows a spacecraft to perform slipspace transitions is generally referred to as a slipspace drive.

Background
Slipstream space is a specific set of eleven "nondimensions" existing in a very small bundle "above" the one temporal and three spatial dimensions perceptible to human beings. By moving matter from the three space dimensions and one time dimension of normal space to slipstream space, one effectively changes the laws of physics for that piece of matter. This allows faster-than-light travel without relativistic side-effects i.e., the occupants do not "warp" time, despite their superluminal speed.

In the year 2291, physicists Tobias Shaw and Wallace Fujikawa were the first humans to successfully implement a device that could safely transition normal matter in and out of slipstream space, the Shaw-Fujikawa Translight Engine. This enabled humanity to begin colonial expansion beyond their home system.

The Covenant utilizes the same eleven dimensions of slipstream space for travel, though the means they use to make the transition are more sophisticated than those used by humans, as evidenced by their markedly faster journeys from point to point.

The Forerunners had a far greater understanding of slipstream space, with the abilities to travel nearly instantaneously over galactic distances, transport massive objects through the use of portals, to disrupt slipstream travel from normal space and track slipspace jumps across the galaxy. In addition, they had developed a great variety of other applications, often involving the manipulation of time and space within a slipspace field.

Mechanics
Slipspace is a tangle of intertwined non-spatial dimensions, comparably similar to a wadded up piece of paper; rather like taking the classic "flat sheet" used to represent gravity and crumpling it up into a ball, thereby creating extra dimensions and shorter spaces between points. Our plane of existence is thought to have four dimensions (up-down, front-back, side-to-side and time), but slipspace is an eleven-dimensional spacetime. Slipspace is entwined with the physical universe to the extent that phenomena in one realm can affect the other, and with sufficiently sophisticated equipment, transitions between the two forms of spacetime are possible. Slipspace is not the only such alternate realm: others include denial of locale, natal void, shunspace, trick geodetics and a photon-only realm known as the Glow, all of which were once discovered and studied by the Forerunners.

Described as non-Euclidean and non-Einsteinian, the slipstream possesses markedly different laws of physics than "normal" space. Due to its different laws of physics, times, masses, positions or velocities in slipspace are impossible to accurately measure based on the standards of normal space. Although they are often used in colloquial contexts, the conventional notions of acceleration, velocity, distance, and time are technically meaningless within slipspace. Even the name "slipspace" is technically a misnomer because the subdomain is non-spatial. Ordinary matter cannot exist in the raw slipstream without being torn apart; ships traveling in slipspace are shielded by carefully-tuned quantum fields which wrap them in envelopes of normal space. Any construction in slipspace itself would have to be composed of specialized forms of exotic matter.

Slipspace is not completely empty; clouds of primordial atomic hydrogen are relatively frequent. Occasionally, even comets are known to somehow find their way into slipspace. Objects close to one another such as fleets often group together in mass slipspace transit and may appear to sensors as a large, singular object. Objects in normal space are intangible in slipspace: an object in slipspace can pass through a mass, such as a planet, without causing a collision in normal space; such an event may often go completely unnoticed. However, there may be risks involved if a ship is still early in slipspace transit and passes through a large object, such as another ship.

Slipspace itself is nonvisible to the human eye, as there is nothing in the visible spectrum to see. To observers aboard spacecraft traveling through slipspace, this means that alternate domain appears pitch black. Slipspace-associated phenomena in normal space, such as the radiation from a slipspace transition, are most commonly luminous blue. In some cases (most prominently in teleportation) these effects may also appear yellow and orange.

Reconciliation
While faster-than-light travel is bound to generate chronological and causal paradoxes by nature, ships traveling through slipspace rely on a self-healing effect of space-time called reconciliation, more formally known as causal reconciliation or particle reconciliation, to eliminate any paradoxes that may otherwise occur. The severity of this effect, which scales in a nonlinear fashion, is determined by the amount of discrepancy in information transfer between locations, as well as strain on the local space-time brane, as opposed to the apparent length of the voyage alone. Mass, or size, is also a contributing factor, at least in the transport of abnormally large objects.

The Forerunners were forced to place significant importance on this phenomenon due to their routine galactic-scale travel. For example, reconciliation has a limited range and time dilation effects may occur if a ship performs a very long jump. The Forerunners prevented this by completing unusually long slipspace journeys in a number of individual jumps, allowing reconciliation to take effect between each. Despite the limitations it placed on them, the Forerunners could also control reconciliation to an extent, enabling them to use its effects against their enemies, hampering and even cutting off their channels of slipspace travel. Early on in their history, the Forerunners used time-phased mirrors to reconcile space-time on a large scale.

Reconciliation has a "budget" — extensive slipspace travel exerts strain on space-time on a large scale as causal paradoxes accrue a "debt". When these aftereffects build up, it can impede with, or in extreme cases, entirely halt other superluminal traffic and communication. Slipspace returns to its normal state as reconciliations are allowed to take effect, gradually causing the space-time debt to disappear into the quantum background. This effect is noticeable if large amounts of mass are transported over long distances frequently, slowing down slipspace travel throughout the galaxy and requiring ships to perform more individual jumps during a journey. This was seen when Master Builder Faber used slipspace portals to transport the Halos, or when the Audacity traveled to the Large Magellanic Cloud. The latter voyage demonstrates the nonlinear scaling of reconciliation: although physically shorter than the trip to the Arks, for example, the other factors involved led to the journey being the most challenging one in the Forerunners' recent memory.

This effect works both forward and backward in the linear time of our universe: by the final weeks of the Forerunner-Flood war, slipspace had already stabilized almost completely due to the galaxy-wide cessation of slipspace travel which would shortly follow with the activation of the Halo Array.

Reconciliation is briefly experienced once a ship returns to normal space, and manifests as a shimmering blue glow radiating out of the ship and static electricity building up in the occupants' bodies; on extremely long jumps or in strained slipspace, the effects experienced by the occupants may by significantly more severe. With Forerunner ships, the effects of reconciliation are clearly noticeable for several seconds after a ship exits slipspace.

Because of modern-day humanity's inferior grasp of reconciliation technology, the time slipspace travel takes to normal-space observers varies substantially; one cannot depend on the same amount of time passing in slipstream space and normal space. With human slipspace travel, there is generally a five- to ten-percent variance in travel times between stars. A fleet that transitions to slipstream space at the same time may or may not transition back to normal space at the same time. Furthermore, if ship 'A' and ship 'B' both were to enter slipstream space at the same time and exit at the same time, the crew on ship 'A' could have experienced a longer journey subjectively, and the crew of ship 'A' could be a week older than that of ship 'B' despite appearances in normal space. Though no human scientist is sure why travel time between stars is not constant, many theorize that there are "eddies" or "currents" within the slipstream. This temporal inconsistency has given military tacticians and strategists fits, hampering an uncounted number of coordinated attacks.

Drive operation
The Shaw-Fujikawa Translight Engine generates a resonance field, which when coupled with the unusual physics of the slipstream, allows for dramatically shorter transit times between stars. UNSC slipspace drives use particle accelerators to rip apart normal space-time by generating micro black holes. These holes are evaporated via Hawking radiation in nanoseconds. The real quantum mechanical marvel of the drive lies in how it manipulates these holes in space-time, squeezing vessels weighing thousands of tons into slipspace. It must be noted that the Shaw-Fujikawa Translight Engine itself provides no motive power, and ships equipped with such a device still require conventional engines in order to move.

Starships and their occupants are not directly exposed to the eleven-dimensional spacetime while moving through slipspace; instead, the ship is enveloped in a quantum field generated by the drive. The field acts as a medium between the ship and the higher dimensions, translating its presence as a normal-space object to the arcane physics of slipspace and enabling it to "squeeze through" the higher dimensions. This field requires an enormous amount of constant calculations to maintain, with the number of needed calculations increasing with the size of the ship. For example, the slipspace translations for a require 4.3 quadrillion calculations of the quantum field per second. The vessel's mass is a noted consideration in the generation of this "buffer" as well as the energy expenditure of the drive in general.

Before jumping into slipspace, human ships must first reach a Safe Slipspace Entry Point, or SSEP, where it can be ensured they will not drag anything from normal space into the slipstream as the ship initiates the transition. In addition, star systems have specific slipstream space transfer points known as "interstellar jump points", or IJPs, locations designated ideal for initiating a slipspace transition.

The Covenant have a very finely tuned version of slipspace technology, far superior to the human Shaw-Fujikawa Translight Engine. Instead of simply tearing a hole into slipspace, Covenant slipspace drives cut a very fine hole in the fabric of space-time and slips into slipspace with precision, much like a scalpel compared to a butcher knife. It exits with the same pinpoint accuracy, takes less time during travel, and is able to plot a course with error not exceeding an atom. This is why in battle Covenant ships are able to slip by human defenses by using slipspace. It has also been theorized by the UNSC that Covenant drives generate several 'microjumps' within a single slipspace transition to measure dilation, allowing them to reach their destinations faster. Standard Covenant tactics include using short slipstream jumps to gain positional advantage and surprise other ships, in addition to avoiding incoming ordnance. The Covenant's superiority in drive technology, combined with differing weapon and shield technology, allows a small number of Covenant ships to effectively engage a much larger UNSC force. Missiles, especially, can be defeated by a brief slipstream jump, as they cannot track through slipstream space.

The Forerunners' advanced slipspace technology allowed them to perform smooth and ultraprecise transitions, enabling ships to reach their destinations with superior velocities, unerring accuracy and without the temporal anomalies commonly experienced by human ships. The restrictions on Forerunner slipspace travel had less to do with technology and more with the inherent nature of space-time which limited their slipspace travel by forcing them to take into account the effects of reconciliation and the overall space-time debt it accumulated. Forerunner slipspace drives used a form of crystal to control and stabilize their slipspace passages; forgoing these crystals would force them into much more chaotic and unpredictable transitions.

Navigation and precision
The plotting of slipspace jumps is known as astrogation, and is typically performed by a navigation computer or an AI, although humans are capable of conducting at least some of the calculations involved. The trajectory of a slipspace jump is already determined by the time the ship enters slipspace; thus, pursuing ships are able to follow the ship which made the transition. This also enables the pursuers, provided they are equipped with superior drives, to overtake the ship they were following through "slipspace supersession"; this occurred when the Covenant Fleet of Particular Justice followed to Installation 04, allowing the Covenant ships to arrive long before the human vessel.

In addition to having to deal with temporal anomalies, UNSC ships are not able to jump with exact precision. A ship may transition back to normal space millions of kilometers from its intended destination. As a result, UNSC ships often transition in and out of slipspace far from any gravity wells of celestial bodies. In-system jumps are also generally considered impractical, even dangerous, by the UNSC due to this lack of precision. A notable exception of this is during the Battle of Psi Serpentis, when the Battle Group India, under command of Admiral Preston Cole, performed an in-system jump. Even though Cole had made thorough calculations for the jump a week in advance and guidance beacons were used as navigational assists, a part of the battle group scattered, reappearing outside the main group.

The Gravemind was able to use the to make a successful precision jump into High Charity. This may be due to an improvement on the ship due to the recent capture of Covenant Slipspace technology, the Gravemind adjusting it or possibly using Installation 05's teleportation grid or related systems to move the ship. Cortana was able to jump the Covenant flagship Ascendant Justice into slipspace inside the atmosphere of the gas giant Threshold following the Battle of Installation 04, a feat previously thought impossible even by the Covenant. Following the Human-Covenant War, a number of UNSC ships, such as the, have been fitted with Forerunner drive technology, granting them near-perfect jump accuracy in addition to far greater velocities.

Gravitational effects
Although they are not present as tangible objects within slipspace, the gravitational pull of large masses, such as stars, affects the geometric trajectory of objects traveling in slipspace much like it would in normal space. This effect typically distorts and scatters clouds of dust drifting in the Slipstream.

Gravitational fields of significant size, such as those generated by a planet, affect the superfine quantum filaments that a slipspace drive must use to calculate an entry point to the slipstream, and UNSC calculations are unable to offset this effect. Covenant drives, in turn derived from Forerunner technology, have a much higher resolution of the filaments, and use more accurate calculations, and though the Covenant do not use this ability, are capable of making slipstream transition in and out of a planet's gravity well. Indeed, while using the captured Ascendant Justice to make a slipspace jump within Threshold's atmosphere, Cortana remarked that "It was as if she was blind before." After observing this innovation, a Covenant AI managed to leak the data out to the rest of the Covenant in a transmission. During the Battle of Mombasa, the Prophet of Regret used this newfound knowledge to transition into slipspace while directly over New Mombasa in Earth's gravity well, damaging the city and causing the weakening and eventual collapse of the orbital elevator there. These events show that, while the Covenant often cannot innovate their own solutions, they are quick to adopt any practice that increases their combat prowess.

Velocities
Because the slipspace drive itself does not generate thrust (instead maintaining the ship's quantum field and transitioning it in and out of slipspace), a ship must still rely on acceleration provided by its conventional drive engines while in slipspace. As a result, ships which are faster in normal space due to their more powerful thruster engines and proportionally small mass, such as corvettes, usually travel faster in the Slipstream as well. The mechanics of the slipspace drive and the way it manipulates the slipspace field have an effect on the time it takes for a ship to cross distances, with more sophisticated drive technology allowing for various methods of crossing distances more efficiently. Frequent traffic, especially when moving objects of considerable mass, will also slow slipspace traffic down on a galactic scale, although this is only known to have occurred when the Forerunners moved the Halo installations across the galaxy.

However fast it may appear, human faster-than-light travel is by no means instantaneous; "short" jumps routinely take up to two months, and "long" jumps can last six months or more for the crew. Certain UNSC ships are known to be able to travel at a speed of 2.625 light years per day, while Covenant ships can reach 912 light years per day. After the end of the Human-Covenant War, the discovery and reverse-engineering of Forerunner technologies allowed humanity to achieve significantly greater velocities. By early 2553, the and  had been equipped with upgraded drives which enabled them to cross interstellar distances in mere hours.

One example of the differences between speeds is comparing the Covenant cruiser Ascendant Justice with the UNSC Halcyon-class cruiser. It took several weeks for the Pillar of Autumn to get from Reach to Installation 04, yet the Ascendant Justice could get from Installation 04 to Reach within thirteen hours from the occupants' frame of reference. However, this may have been due to the influence of the Forerunner crystal, which simultaneously caused the Ascendant Justice to go back in time for several days as a result of its occupants being on an event path intersecting the crystal.

Though the Covenant use a modified version of Forerunner systems, true unaltered Forerunner slipspace technology was first observed in the form of the Portal transporting UNSC and Covenant vessels from Earth to The Ark, transporting them hundreds of thousands of light years within a month. Additionally, while a Covenant assault carrier could reach Delta Halo from Earth in thirteen days, the Forerunner Dreadnought took only five days to travel the same distance. Given the fact that Covenant understanding of Forerunner technology is comparatively primitive, the ship may have been capable of much higher velocities. This is very likely as the Mantle's Approach was able to travel from the vicinity of Installation 03 to Earth in a matter of minutes.

Dangers and risks
Direct exposure to the Slipstream is incredibly dangerous. Despite the presence of a quantum field which effectively keeps the ship within a "bubble" of normal space, people traveling on a slipspace-capable craft can experience a range of symptoms, from nausea, to heart failure or even death. It is also known that some people react to slipspace jumps stronger than others. Even more uncommon, but still known to happen, is the total disappearance of a person while in the slipstream.

Slipspace travel is also dangerous due to the high level of radiation encountered during the trip, which can be extremely hazardous to the crew. This is negated by the use of lead foil in UNSC ships, which absorbs the radiation. Fissile materials also emit radiation, specifically Čerenkov radiation, upon exiting Slipspace; this is not harmful to humans, however it does make emerging from Slipspace very noticeable. It is not known how the Covenant deal with radiation, but it is presumed that either they also utilize a shielding material, or with their improved slipspace technology and energy shielding, it does not affect them at all. In addition, slipspace travel generates a great deal of static electricity on the ship's hull. To discharge the static energy, humans have developed a piezoelectric material known as polymerized lithium niobocene.

Since the Slipstream is constantly shifting, and its laws of physics are different to our own, the magnetic coils of Slipspace drives drift out of phase when entering and leaving a Slipspace field, requiring constant maintenance. During the 2490's, technicians had to manually repair Slipspace drives, exposing themselves to the Slipstream and occasionally suffering injury, death or simply disappearing. Mechanical failures like Slip Termination, Preventable, or STP, can also occur with Slipspace drives, usually resulting from poor maintenance. An improperly mounted Slipspace drive can also result in catastrophic accidents, as was the case with a colony ship en route to the Cygnus system in the mid-2550's: as a result of a maintenance failure, the drive tore the ship apart, transporting half of it into an unknown location. During the Fall of Reach, the UNSC intentionally recreated the conditions of this accident to destroy a Covenant supercarrier.

Prior to 2552, entering slipspace from the gravity well of a planet had never been attempted, either by the UNSC or the Covenant. The effect of gravity upon the creation of a slipspace entrance usually collapsed UNSC-generated holes, and was assumed to be the same with Covenant technology. The flagship Ascendant Justice, however, was able to escape from a gas giant's gravity well after Cortana realized that it had a far higher resolution of the quantum filaments that allowed a transition, and she was able to compensate for the gravity. Subsequently, the ability was transmitted by a Covenant AI, and the Prophet of Regret used an in-atmosphere slipspace jump to escape Earth, with the resulting shockwave dealing devastating damage to the city of New Mombasa. Slipspace jumping inside an atmosphere, however, is extremely dangerous to the surrounding people and objects. When a ship transitions into normal space in-atmosphere, the air that was there is pushed aside, causing a massive shockwave centered at the ship. If a ship transitions to Slipstream space inside an atmosphere, on the other hand, it leaves an empty space that air quickly rushes to fill, causing an implosion. An in-atmosphere jump is also known to cause prominent meteorological aftereffects; the air becomes saturated in an electric blue haze and luminescent clouds emanating from the point of the transition for nearly half an hour. Exiting slipspace in-atmosphere is generally far less destructive than entering it, as ships have done so numerous times without disastrous effects.

Entering and exiting the slipstream is normally only attempted by ships of large mass, their gravity wells stabilizing the constantly fluctuating slipspace to a degree that allows safe passage. Small ships, such as dropships, do not possess the same gravity and are placed under considerably more stress than a warship, able to crack the hull and buckle reinforcing struts. It is not impossible, and UNSC slipstream monitoring probes make the transitions all the time, but require heavy reinforcement to survive the stresses, and are unmanned, having no need to protect internal occupants. Specialized craft like Long Range Stealth Orbital Insertion Pods can make the transition, but are still an extremely uncomfortable ride. A Slipspace-to-normal space transition has been successfully attempted by a Spirit dropship, but it had been extensively equipped with Titanium-A battleplates, lead, and carbon-molybdenum steel I-beams.

Even the Forerunners had potential dangers when traveling through slipspace. During the assault on the Capital by Mendicant Bias, seven of the twelve original Halo rings in existence at the time attempted to flee using a slipspace portal. Only one of them, along with Bornstellar Makes Eternal Lasting's ship made it through. The rest were destroyed when the slipspace portal closed due to the stress of the Halo installations passing through. The enormous amount of mass passing through simultaneously also put massive strain on the slipspace portal, causing any occupants to be dangerously exposed to the foreign physics of slipspace. This resulted in causal reconciliation effects far more severe than normal, as well as symptoms involving the loss of perception of reality and time, massive amounts of electrical charge, even depriving the occupants of solidity for a time. After such an event, a slipspace channel may not return to a stable state for years.

There are also realms of slipspace distinct from the one typically used for travel. A spacetime-manipulating crystal found on Reach caused the UNSC-captured Ascendant Justice and the Covenant ships which pursued it to enter an anomalous slipspace dimension different from the normal slipspace used for travel.

Slipspace wake
A "Slipspace wake" is a phenomenon occurring for some time after a ship has made a slipspace transition. When another, slower ship encounters a slipspace wake, they will be pushed to the speed of the ship that left the wake, thus propelling them through Slipspace at the same velocity. The took two weeks to get to Installation 05 via the Solemn Penance ' s weakening "wake", but came back to Earth within hours by following the Forerunner Dreadnought's wake. The crew of the Dusk later exploited the Bloodied Spirit ' s outbound wake to get to Onyx, thirty-eight light years away, within an hour.

Anomalies
In rare cases, various types of anomalous phenomena occur in slipspace. These may be caused by specific artifacts or devices. The effects of these anomalies are diverse, but often harmful. The Forerunner crystal found on Reach was capable of creating a distortion in Slipspace, but it also generated massive amounts of radiation. In November 2552, the slipspace transition of the Forerunner Dreadnought caused an anomaly within the dimension YED-4.

Communications
Slipspace has been used as the basis for some (although not all) forms of faster-than-light communications system, enabling communication across the vast distances of space in reasonable timescales. First utilized by the Forerunners, such technologies were later appropriated for use by the modern civilizations of the Covenant and humanity.

Teleportation


Slipspace can also serve as means of virtually instantaneous transport over short distances. Originally developed by the Forerunners, Slipspace translocation technology allows its user to safely pass between two locations by enveloping the user in a Slipspace field and transporting them to the intended destination. The Forerunners utilized this technology to a great effect, using it in teleportation grids and transportation pads encountered on many of their installations. Later, the Covenant also adopted this technology and are known to have used it in their gravity thrones and spires.

AI housing
A possible application of slipspace is the use of its eleven-dimensional spacetime as a platform for abstract fractal housing and processing structures for "smart" artificial intelligence constructs. The extra dimensions would grant AIs faster-than-light processing speeds but more importantly, it would give unlimited room for extended neural linkages—by extension, making the AI virtually immortal, free from the limitations of a Riemann matrix, which normally cause a smart AI to descend to rampancy. So far, this has only been attempted once, by Dr. Catherine Halsey in an unsanctioned experiment in 2547. Though the experiment was a failure, the AIs of the Assembly recognized it as a viable means of gaining permanent independence from their creators.

Forerunner applications
The Forerunners had developed a great deal of applications for the slipstream. These included the ability to create bubble-like enclosures of slipstream space, in which the flow of time could be manipulated or stopped altogether while keeping the contents of the bubble either visible or invisible in normal space. The Forerunners were also capable of containing these bubbles of alternate space-time within one another. These bubbles could be used to store considerable masses and volumes in slipspace stably for thousands of years and potentially for all of time, and to transition matter from normal space to the inside of a construct in slipstream space without requiring the construct to transition back to normal space. The same technology was utilized in slipspace field pods that were essentially a Forerunner equivalent of cryo-chambers, effectively preserving a living organism inside a slipspace field. Slipspace bubbles were also employed in a type of Forerunner prison cell in which the passage of time could be manipulated so that a period of a billion years would pass inside the field, while only seconds had transpired in normal space.

In addition, the Forerunners had the ability to construct weapon systems that could fire into slipspace and affect targets in normal space or within slipspace. This is demonstrated by the Line installations of the Jat-Krula boundary, which were capable of intercepting ships in slipspace. In its final battle against Mendicant Bias, the Forerunner AI Offensive Bias used slipspace ruptures generated by its warships to warp the laws of physics around them and tear Mendicant's ships apart.

Slipspace portals created by the Forerunners could be used send objects into slipspace and have them exit in different locations. The Forerunners were also capable of generating slipspace conduits which could anchor objects in normal space into place, as shown when the was constrained over Requiem by an array of slipspace artifacts.

Similarities
Slipspace fills a common niche found in most space science fiction media, allowing ships to travel vast distances in a small amount of time, allowing convenient travel through the galaxy. Though other series use different methods, it is most similar to hyperdrives, which similarly burrow into other dimensions where faster than light (FTL) travel without the relativistic side-effects is possible. Other series use different methods, allowing actual FTL travel in normal space, or instantaneous teleportation, but the principles still follow a similar trend.

Slipspace can be likened to the discovery of matterwave transport without transit. In this process, all seven hidden spatial dimensions, three known spatial dimensions and two time dimensions appear to collapse into a singularity to an outside observer. But in reality, this is only an illusion. In this type of field, relativity predominates, for instance the reality is dependent on the radial displacement from the source that generates the field. At small distances, reality is relatively intact. The further away from the field source, the less sense it makes to talk about reality; a cause can occur after an effect, time has no linear flow. Nothing has a definite momentum or velocity. Objects can occur at multiple positions simultaneously. When an object enters a field, it produces a burst of neutrinos, antimatter and other types of radiation. Slipspace is also similar to a controversial theory known as the Heim Theory.

List of appearances

 * Halo: The Fall of Reach
 * Halo: Combat Evolved
 * Halo: The Flood
 * Halo: First Strike
 * i love bees
 * Halo 2
 * Halo Graphic Novel
 * Halo: Ghosts of Onyx
 * Halo 3
 * Halo: Contact Harvest
 * Halo: The Cole Protocol
 * Halo Wars: Genesis
 * Halo Wars
 * Halo 3: ODST
 * Halo Legends
 * Odd One Out
 * Origins
 * The Package
 * Halo: Evolutions - Essential Tales of the Halo Universe
 * Midnight in the Heart of Midlothian
 * Dirt
 * The Impossible Life and the Possible Death of Preston J. Cole


 * Halo: Blood Line
 * Halo: Reach
 * Halo: Fall of Reach
 * Boot Camp
 * Covenant
 * Invasion
 * Halo: Cryptum
 * Halo: Glasslands
 * Halo: Combat Evolved Anniversary
 * Terminals
 * Halo: The Thursday War
 * Halo 4: Forward Unto Dawn
 * Halo 4
 * Spartan Ops
 * Halo: Spartan Assault
 * Halo: Escalation
 * Halo: Mortal Dictata
 * Halo 2 Anniversary