Book of Abraham
- "Despite my warning, I glance at the page. It is blank. Both pages are blank. Suddenly, symbols fill my mind!"
- ―Giovanni Borgia, upon looking at the Book.[src]
The Book, entitled Divine Science, was used in Bombastus' study to learn how to create gold from other elements. It was an unadorned tome that seemed to be made up of blank pages, but it filled people's minds with ideas when read.
History
Transmutation
Once, after having looked at the Book, Bombastus' apprentice Johan apparently went mad, once raving that "My mind is a small, small cup. Overfilled! Bursting! Cracked!" This suggests that madness can come from learning too much from the Book at once. To guard against this, Bombastus often read the Book with his hands at the sides of his eyes as blinders.[1]
When Giovanni Borgia read the Book's pages in 1520, he was enlightened by knowledge of a certain formula, which he quickly wrote down. Upon following the instructions, he and Bombastus discovered it to be the method of crafting the Philosopher's Stone.[1]
Search for the Second Half
In 1527, Giovanni returned to Bombastus to ask further questions, none of which Bombastus answered. Giovanni then demanded that he read the Book, as it held the answers he sought, but Bombastus confessed that it was incomplete, and that he would need "the other half."[2]
Giovanni then began to research at the university library, along with one of Bombastus' apprentices, Maria Amiel. They discovered that the Book was one of a pair of journals written by a French alchemist, Flamel, which contained the knowledge of Abraham of Würzburg. The first was entitled "True Magic," and the second, "Divine Science."[2]

The two travelled to Paris to search for the manuscript, and discovered that the nephew of Perenelle Flamel had inherited a grimoire. They searched the man's house, but only discovered that the grimoire had been "translated by human hands," and that only the original would suffice.[2]
The translation they found contained the teachings of Pythagoras and other Hermetic practices, prompting Giovanni to recall the Temple of Pythagoras that had once been explored by Ezio Auditore and Leonardo da Vinci.[2][3]
Return to Basel
Upon discovering a spy who knew about their search for the Book, Giovanni and Maria returned to Basel, fearing for Bombastus' life. However, they soon discovered that the professor had gone mad, much as Johan once had, burning books and demanding that Doctors halt their "unholy practices."[2]
After leaving Bombastus at a friend's house for care, they broke into his laboratory to steal the first half of the Book, then travel into the Pythagorean Vault.[2]