Douglas Adams was a cult British comic radio dramatist, musician and author, most notably of The Hitchhiker's Guide to the Galaxy series. Hitchhiker's began on radio and developed into a "trilogy" of five books (which had sold more than fifteen million copies by the time of Adams's death) as well as a television series, a computer game and a feature film that was completed only after Adams's death. In addition, Douglas Adams also wrote or co-wrote three stories of science fiction staple Doctor Who and served the series as Script Editor during the seventeenth season. His other written works include the Dirk Gently novels, co-author credits on two Liff books and Last Chance to See, which was also based on a radio series. Towards the end of his life, he was a sought-after lecturer on topics including technology and the environment. Since his death at the age of 49, he is still widely revered in science fiction and fantasy circles.