Halo Encyclopedia (2009 edition)

This article is about the original 2009 Halo Encyclopedia. For other editions, see Halo Encyclopedia. For the Halo Channel feature, see here.

The Halo Encyclopedia: The Definitive Guide to the Halo Universe is an official guidebook of the Halo universe, published by Dorling Kindersley and created in conjunction with 343 Industries. The encyclopedia has a foreword written by Frank O'Connor, head of 343 Industries, with Tobias Buckell editing. The cover of the book was illustrated by Craig Mullins.

The original edition of the Encyclopedia was released on October 19, 2009. An updated edition of the Halo Encyclopedia with an extra sixteen pages (including information on Halo: Reach) was released on September 19, 2011.

Content review
The Halo Encyclopedia begins with a foreword by Frank O'Connor. It then introduces the Master Chief, the Covenant and many other aspects of the Halo universe. Chapter One contains a timeline (complete to publication), followed by chapters on humans, Spartans, the Covenant, the Flood, the Forerunners, the Human-Covenant War, science and technology, transport, locations and finally weapons - before a glossary of terms, index and acknowledgments.

Reception and errors
Reception to the Halo Encyclopedia has been mixed. Some reviewers and readers praised the book's detailed approach to its content. However, other reviewers stated that the book's images are often of poor quality and "at times seem haphazardly thrown together." Others criticisms centered on the work's poor editing, most notably its poor spelling and grammar. Misattributions are also frequent, with the Scout and Rogue armor being referred to as one armor type. Later printings of the Encyclopedia feature improved editing, eliminating many mistakes that exist in the initial printing, including several mislabelings and misattributions. Nonetheless, several factual inaccuracies remain. For example, the ranking system of the Brutes is mangled, with a picture of a Major labeled as a Minor, and the color of an Ultra's armor is mis-cited as cyan instead of violet.

It has also been noted that a number of descriptions in the book are ostensibly based upon, even quoted from, those of Halopedia. This has also resulted in several errors. Examples of such content include:
 * As the the first official source to establish the development of the Mark-based generations of the MJOLNIR Powered Assault Armor prior to the fifth generation, the Encyclopedia appears to have based this information on fan assumptions and outright fanon found in early Halopedia. Specifically, pre-Encyclopedia sources never specify that the armor issued to the Spartan-IIs in 2525 was the MJOLNIR Mark IV; only the Mark V is mentioned by name in the promotional material for Halo: Combat Evolved, while Halo: The Fall of Reach does not specify any Mark generations in reference to MJOLNIR, only mentioning the pre-MJOLNIR Mark I exoskeletons. Although it is understandable to assume based on the narrative of the The Fall of Reach that no intermediate generations of MJOLNIR armor were issued between the two scenes in which new MJOLNIR generations are explicitly shown, this is nonetheless nothing more than an assumption as the narrative skips over most of the war. The Encyclopedia ' s descriptions of Marks I through III are also directly based on unsourced information added to Halopedia in 2006, which lacks any pre-Encyclopedia canonical backing. Although this timeline has been embraced by later canon, it creates a questionable situation where the first three generations of MJOLNIR are relegated to pre-production prototypes, while the Mark IV remains in service for most of the war. This may also have necessitated the broad-strokes treatment the Mark system has received in subsequent works, with Dr. Halsey's personal journal establishing that the Mark IV alone was an ever-evolving platform encompassing multiple distinct models of suit.
 * The Encyclopedia splits the Battle of Earth into a "First" and "Second" battle, a decision originating from Halopedia, until newer information from Halo: Ghosts of Onyx and Halo 3: ODST established that the battle was in fact one continuous engagement.
 * Another error has even had impact on the series canon outside the Encyclopedia itself: the book mentions a faction of Insurrectionists named the "United Rebel Front" or "URF"; this name originated from Halopedia, which had mistakenly interpreted the descriptive term "united rebel front", mentioned in Ghosts of Onyx, as a proper name. In addition, the rebel destroyer Origami is designated "URF Origami", which is also based on an earlier version of the ship's Halopedia article; no previous official source mentions the rebels using such a ship prefix. Even though Halopedia later corrected this mistake, the misunderstanding persisted and led to the United Rebel Front being integrated into newer works of official fiction.
 * The Secessionist Union and the People's Occupation Government are stated to be the same organization, a claim clearly originating from Halopedia, as the original source for the two groups does not indicate they are synonymous.
 * Shield World 006 is referred to as "the Sharpened Shield", which was a short-lived fan-given name for the installation on Halopedia.

2011 revised edition
The 2011 edition incorporates new content, mainly image assets, from Halo: Reach, as well as correcting some mislabeling in the original. However, many of the errors remain. 343 Industries Content Creator Jeremy Patenaude has acknowledged that many of the errors remain in the new edition, and stated that future efforts to create a Halo universe encyclopedia would be rewritten from the ground up.