More than a mere book, it is also a piece of ancient technology: the actual frame and protective casing acted as a conduit for Primal energy, channel it into a 'raw and usable state'. The signet ring required to unlock the book also acted as the trigger mechanism, allowing the book's 'frame' to function in this way as a completed circuit.
The "pages" of the book also contain Glyphs that provide instructions on the ritual used to harness Primal energy.
- There are two known copies of the book: the first was delivered to Baron Northcrest and used in the initial channeling of the Primal in the prologue of the game; it was destroyed in the ritual. The second was found in the ruins of the ancient Keeper Library, below the current South Quarter. This one was commissioned to be stolen by Garrett for Orion, and later used to conduct the same ritual in both the Hidden City and aboard The Dawn's Light. It is unknown if this copy of the book was destroyed.
- The book holds its origin with the Keepers from the original Thief series, as it holds a similar design to many books depicted in the briefings of The Dark Project (locks on heavy, metal-bound books such as the Compendium of Reproach could only be opened using Glyph magic).
- The gear shape looks incredibly similar to the symbol of the ancient Mechanist Order.