a real world point of view
Decide Your Destiny was a series of BBC Books Doctor Who books. These were gamebooks, written in the second person with branching narratives: so, for example, at the end of a page there would be two or more options (for example, "to go right, go to page 56. To go left, go to page 77") and tell you which page to go to. This style of gamebook is frequently called Choose Your Own Adventure, after a long-running series of books that began in the late 1970s and popularised this genre of "interactive" novel; however, the term "Choose Your Own Adventure" properly refers to this line only. Decide Your Destiny follows a number of Doctor Who-related gamebooks in this genre dating back to the mid-1980s.
Originally featuring the Tenth Doctor, the books continued into 2010 with the release of editions featuring the Eleventh Doctor. Unlike previous Decide your Destiny titles, all four 2010 books appear to feature the return of a monster or alien that has appeared on T.V. These creatures are the Macra, Sycorax, Judoon and Werewolf. They also have links to exclusive online content.