Attack on Titan Guidebook, also known as Attack on Titan Guidebook: INSIDE & OUTSIDE, is the English version of the first two official guidebooks for the Attack on Titan manga, Attack on Titan: INSIDE Kou and Attack on Titan: OUTSIDE Osamu, which combines both books into one and uses the cover of the latter. It was written and illustrated by Hajime Isayama (in the original Japanese version) based on the first 11 volumes of the manga and is 320 pages long. It was released on September 16, 2014.