This article's content is accurate to the most recent public game version, 0.4.8d.
"A book written in blood. You have no idea what language it is written in."
The Tome of the Night is a key item found in the Sealed Archives on the leftmost table of the three tables in a row on the west side, the one closest to the wall. It actually serves no purpose, simply being one of the extra books used to distract the player from the correct answers to the puzzle.