Pilfer the Prophecies is a contract in Mission 4 of Dishonored Death of the Outsider.
Pilfer the Prophecies Walkthrough
While murdering your way through the Royal Conservatory for the Alvaro and the Abbey contract, make your way to the 3rd floor. On the east end of the building is an elevator with a corpse on top of it, stuck between floors. On the corpse is a notice for the Pilfer the Prophecies contract, and inside the elevator are the prophecies themselves. Drop down through the roof hatch, pick up the book, and your contract is complete.
All Mission 4 Contracts: