On Apocrypha is a series of four volumes found while reading Black Book: Waking Dreams which are used to solve a puzzle. The four volumes in the set include:
- On Apocrypha: Boneless Limbs
- On Apocrypha: Delving Pincers
- On Apocrypha: Gnashing Blades
- On Apocrypha: Prying Orbs