Halo: Silentium

Halo: Silentium is the third and final novel in The Forerunner Saga by Greg Bear. It is the sequel to Halo: Primordium. It was released on March 19, 2013, with an audio edition released simultaneously.

Official summary
"In the last years of the Forerunner empire, chaos rules. The Flood — a horrifying shape-changing parasite — has arrived in force, aided by unexpected allies. Internal strife within the ecumene has desperately weakened Forerunner defenses.

''Too little, too late, the legal rate of Juridicals is only now investigating possible crimes by the Master Builder and others. Evidence-gathering agents known collectively as Catalog have been dispatched to collect testimony from the Librarian and both Didacts: the Ur-Didact, treacherously abandoned in a Flood-infested system, and the Bornstellar Didact, who accompanies the Librarian as she preserves specimens against the dire possibility of Halo extermination.''

Facing the imminent collapse of their civilization, the Librarian and the Ur-Didact reveal what they know about the relationship between the long-vanished Precursors and the Flood.

''The Precursors created many technological species, including humanity and the Forerunners. But the roots of the Flood may be found in an act of enormous barbarity, carried out beyond our galaxy ten million years before...''

''Because of that barbarism, a greater evil looms. Only the Ur-Didact and the Librarian -- husband and wife pushed into desperate conflict -- hold the keys to a solution.''

Facing the consequences of a mythic tragedy, one of them must now commit the greatest atrocity of all time — to prevent an insane evil from dominating the entire universe."

Forerunners

 * Birth-to-Light
 * Bitterness-of-the-Vanquished
 * Boundless
 * Carrier-of-Immunity‎
 * Catalog
 * Celebrator-of-Birth‎
 * Chant-to-Green
 * Clearance-of-Old-Forests
 * Dawn-over-Fields
 * Endurance-of-Will
 * Examiner
 * Faber
 * Glow-of-Old-Suns
 * IsoDidact
 * Keeper-of-Tools
 * Librarian
 * Maker-of-Moons
 * Sharp-by-Striking
 * Tactician
 * Ur-Didact

Artificial intelligences

 * 343 Guilty Spark
 * Haruspis
 * Mendicant Bias
 * Offensive Bias

Humans

 * Forthencho

Promotion
On February 11, 2013, an announcement was released on Halo Waypoint that in the weeks leading up to the release of Silentium Tor Books and 343 Industries would be sending out encrypted communications via halowaypoint.com bulletins and forums, which will allow fans to unlock additional content. There will also be embedded data in the text of the Halo: Silentium paperback and e-book editions. Players can unlock this content in the Classified menu at Halo Waypoint. The unlocked contents are 20,000 experience points for multiplayer and an audio video called "Rebirth", a story narrated by Greg Bear and acts as an epilogue for Silentium. It tells the story of Riser and his last encounter with the IsoDidact.

Trivia

 * "Ur" is a German prefix that means "original" or "primitive".
 * "Silentium" is Latin for "silence", "stillness", "inactivity" or "cessation", which reflects the effect of the Halo Array's galaxy-wide activation on the Forerunner civilization and life in the galaxy.
 * The preliminary cover art, illustrated by Nicolas "Sparth" Bouvier, depicts a vast Forerunner structure with a Cryptum floating in the center and several ships flying by, while the final cover art depicts the Didact observing a hologram of a Cryptum and his wife, the Librarian; the preliminary cover image remains in the background. The original cover illustration was used to promote the novel without giving spoilers as to the appearance of the Forerunner characters, which was not revealed until Halo 4. The final cover art was done as a collaboration between Sparth and Halo 4 concept artist Gabriel Garza.
 * The novel was originally set to be released on January 8, 2013, but the release was later delayed to March 19, as additional time was required to make the story of the novel fit seamlessly with that of Halo 4.