Mark London Williams, born June 19, 1959, is an American author, playwright, journalist, and creator of the young adult time travel series Danger Boy. Starting in 2019, the series follows the time spanning adventures of twelve year old Eli Sands, the eponymous protagonist, and his companions: Clyne, a good-natured dinosaur from another planet who gathers information for a school assignment, and Thea, last librarian in Alexandria. In 2001, the first two books were initially published as trade paperbacks (Book I simultaneously in hardcover) by Tricycle Press with covers by J.H. Williams III, Mick Gray, and Jeromy Cox. Starting in 2004, Candlewick Press re-issued the partially re-written first two books and produced the successive new volumes in uniform hardback editions all with covers by Michael Koelsch. The first two books of the Candlewick editions were re-issued as trade paperbacks with the hardback covers. The first Danger Boy adventure Ancient Fire was nominated for The Golden Duck Awards for Excellence in Children's Science Fiction: Hal Clement Award for Young Adults.