The Book of Future Legends was a Gallifreyan book used by the Pythia to foresee the future, although its prophecies were usually enigmatic. It told of the Amphisbaena, and that the Pythia's successor would be male. It was rumoured that the return of Prydonius was also a Future Legend. By the Doctor's time, the book was a relic, all its predictions having been fulfilled ages ago. (PROSE: Cat's Cradle: Time's Crucible)