In the *Harry Potter* universe, Flamel's book is:
* The Book of Abraham the Mage: A magical book that contains powerful spells and secrets about alchemy and immortality.
* Not a physical book: It's actually a magical scroll that Flamel carries with him.
The book is an important plot point in *Harry Potter and the Sorcerer's Stone,* where it's revealed that the Sorcerer's Stone is being guarded by Flamel, who is using it to extend his life. The book itself is never actually shown or described in detail, adding to its mystique.