到目前为止，第三版刺客信条百科全书拥有游戏系列最多内容的信息，内容超过390页。 第二版百科全书共计384页。 第一版百科全书共计256页。
The Characters section contains profiles on all the characters features in the series, beginning with Desmond Miles and the allies and enemies he encountered. After this, it details the ancestors of Desmond, including Aquilus, Ezio Auditore da Firenze and Altaïr Ibn-La'Ahad.
The profile of Aquilus describes the confrontations between him and the Templars, both in their struggle for the Shroud of Eden and the Ankh.
Altaïr's profile is expansive and details his entire life, finishing with his death inside his library in 1257. After his profile, it gives information on all of his assassination targets, allies and other enemies he combated within his time.
Ezio's profile is quite large compared to Altaïr's. It once again details his life and the allies and enemies he encountered. It adds on, however, with explanations of the Venetian and Florentine conspirators and the confrontation in Constantinople.
Ratonhnhaké:ton's profile details his life throughout Assassin's Creed III. Similar to Ezio's profile, it details his life, friends, the allies and enemies he encountered during the events in Assassin's Creed III, the latter such as the American Revolutionary War.
Aveline de Grandpré's profile is much the same as Connor's in that it details her life throughout Assassin's Creed III: Liberation, the friends & allies and enemies she encountered along the way.
Daniel Cross' section outlines how the Templars experimented on him during his youth and his infiltration of the Assassins, whilst including profiles on the people he encountered, including Hannah Mueller, Paul Bellamy and the Mentor.
- On the spine of the Encyclopedia, there was a hidden message written in Unicode. Once translated, and after removing the title in red, the message read "Three lives toiled. Three lives lost. Three messages delivered: the greeting, the warning, the revelation."
- At E3 2012, new editions of the Encyclopedia featured a quote from the Bible written in hexadecimal code instead: "We saw the Nephilim there; We seemed like grasshoppers in our own eyes; And we looked the same to them." (Numbers 13:33). This quote is also spoken by William Miles to Desmond in Assassin's Creed III, after the latter complained about Juno only ever leaving cryptic messages.
- On multiple pages, a molecule was drawn with a benzene ring and a hydrogen atom with two bonds. However, since hydrogen has only one electron to react with, it cannot form a double bond.
- The encyclopedia mainly uses concept art as pictures, as opposed to CGI renders.