Oolon Colluphid

Oolon Colluphid was the author of the book Origins of the Universe, which the Fourth Doctor had in his pocket and used as a way to pass the time while pinned down by fallen rubble. Paging through the book, the Doctor noted "He got it wrong on the first line!" and wondered "Why didn't he ask someone who saw it happen?". (TV: Destiny of the Daleks)

Behind the scenes
The character of Oolon Colluphid was mentioned in Douglas Adams' The Hitchhiker's Guide to the Galaxy. Adams served as script editor for Destiny of the Daleks and occasional Doctor Who script writer. The Hitchhiker's Guide series also exists as a fictional work in the Doctor Who universe. However, due to the existence of the book in Destiny of the Daleks, it is possible that some elements of The Hitchhiker's Guide to the Galaxy do in fact exist within the Doctor Who universe. Cross-dimensional travel has been utilised on more than one occasion in both properties, so it's possible that the book might not even be from the regular DWU.