The Will and Order of St. Dumas is an ancient text detailing the history of the Dumas family and their ancestors.
The book described the ancestors of the Dumas family and detailed that they were descendants from 12th Century Knights, one of them being Azrael. Theo Galavan studied the book and memorized the entire thing. After his death and later resurrection at Indian Hill by Professor Hugo Strange, his memories were fractured and he began reciting passages from the book. Strange used this to his advantage to brainwash Galavan into believing he was Azrael brought back to life, and sent him on a mission to murder Jim Gordon.