The History of the Time War

The History of the Time War was a book chronicling the history of the Last Great Time War, possibly written, at least in part, by the Doctor; given that, as the only survivor, he was the only one able to write the ending. It contained the name of the Doctor. The Eleventh Doctor kept the only known copy of the book in his TARDIS' library, which Clara Oswald once read whilst running from a time zombie. She lost the knowledge of what she had read when the Doctor changed their timeline. (TV: Journey to the Centre of the TARDIS)

It was written in Gallifreyan, raising questions on how Clara Oswald could have read it.