David Llewellyn is a Welsh novelist and script writer. He grew up in Pontypool and graduated from Dartington College of Arts in 2000. His first novel, Eleven, was published by Seren Press in 2006. His second, Trace Memory, a spin-off from the BBC drama series Torchwood, was published in March 2008. Everything Is Sinister was published by Seren in May 2008. He has written two novels for the Doctor Who New Series Adventures: The Taking of Chelsea 426, featuring the Tenth Doctor, and Night of the Humans, featuring the Eleventh Doctor and Amy Pond. In addition to writing novels, Llewellyn wrote the Bernice Summerfield audio play Paradise Frost and the Dark Shadows audio drama The Last Stop for Big Finish Productions. Llewellyn lives in Cardiff.

See also works published as Andrew Lane During 2009, Macmillan Books announced that Lane would be writing a series of books focusing on the early life of Sherlock Holmes. The series was developed in conjunction with the estate of Sir Arthur Conan Doyle. Lane had already shown an extensive knowledge of the Holmes character and continuity in his Virgin Books novel All-Consuming Fire in which he created The Library of St. John the Beheaded as a meeting place for the worlds of Sherlock Holmes and Doctor Who. The first book in the 'Young Sherlock Holmes' series – Death Cloud – was published in the United Kingdom in June 2010 (February 2011 in the United States), with the second – Red Leech – published in the United Kingdom in November of that year (with a United States publication date under the title Rebel Fire of February 2012). The third book – Black Ice – was published in June 2011 in the UK while the fourth book – Fire Storm – was published originally in hardback in October 2011 with a paperback publication in March 2012. The fifth book, Snake Bite was published in hardback in October 2012 and the sixth book, Knife Edge was published in September 2013. Death Cloud was short-listed for both the 2010 North East Book Award. (coming second by three votes) and the 2011 Southampton's Favourite Book Award. Black Ice won the 2012 Centurion Book Award. Early in 2012, Macmillan Children's Books announced that they would be publishing a new series by Lane, beginning in 2013. The Lost World books will follow disabled 15-year-old Calum Challenger, who is co-ordinating a search from his London bedroom to find creatures considered so rare that many do not believe they exist. Calum's intention is to use the creatures' DNA to help protect the species, but also to search for a cure for his own paralysis. His team comprises a computer hacker, a free runner, an ex-marine and a pathological liar.