The Halo Encyclopedia is an official guidebook of the Halo Universe published by Dorling Kindersley. The encyclopedia has a foreword written by Frank O'Connor, the Halo franchise director, and was edited by Tobias Buckell. It was released on October 19, 2009. An updated version was released on September 19, 2011. There are two editions of the book. The first edition contains information about Halo: Combat Evolved, Halo 2, Halo 3, Halo 3: ODST, and Halo Wars. The second edition is the same as the first, but with information about Halo: Reach.