- "A work of fiction; charmingly idealistic in some of its conceits, if not wrongheaded."
- —Nathaniel's opinion of the Apocrypha[src]
The Apocrypha was a collection of the lost writings of Ptolemy of Alexandria. Following his murder, his scattered papers, including those describing the process of creating the Gate of Ptolemy, were put together in the Apocrypha. Most serious magicians regarded the work as a speculative fantasy. The book was only ever published in ancient Greek.
Over the centuries, some magicians sought to understand Ptolemy's writings and use the Gate, but only for the usual ends of increasing their own power. These attempts all failed miserably, convincing future generations that the Apocrypha's knowledge was nothing more than fantasy, and the book was neglected.
Kitty Jones's first job for Harold Button was to deliver him a copy of this book, which he had long desired to study. Despite Button's nature, however, he too did not place much stock in some of the more unusual ideas of the book. After Bartimaeus explained to her the concept of the Gate of Ptolemy, Kitty took the copy of the book for herself. She had to rely on Nathaniel to read it for her, as she did not know how to read ancient Greek.