The Book of Revelation is a written work within DEXTER. Created by author John the Revelator, it tells of the End of Days (a concept for the birthing of the New World) brought upon by Two Witnesses.

An Early A.D. Cult known as the Enesserrette believed that this book was a Code for triggering the End of Days. Later, a man named Professor James Gellar deciphered this code as seven sacrifices. Gellar wrote down the notes required for each of these sacrifices, which Travis Marshall later discovered. Travis took it to heart that he was one of the witnesses and that Professor James Gellar was the other one. Travis's goal was to bring about the End of Days by enacting each of seven signs (referred to as Tableaus).

Passages from the book were referenced multiple times in the Doomsday Killer Investigation, specifically by Mike Anderson who researched and prepared large printouts of different verses within the text.