Born in Windsor, England in 1944, Nimmo's father died when she was only five. By the time she was fourteen, she had gone to two boarding schools and had joined a theater company in England. Her unstable childhood led to a series of diverse jobs where she worked in several fields as a nanny, a photographic researcher, and a floor manager at the BBC. At the BBC she became a director of Jackanory, a children's show. After having her first child, Nimmo left the BBC and began work on her first novel, "The Bronze Trumpeteer." Nimmo is best known for two series of fantasy novels: The Magician Trilogy (1986 to 1989), contemporary stories rooted in Welsh myth, and Children of the Red King (2002 to 2010), featuring Charlie Bone and other magically endowed school children. The Snow Spider, first of the Magician books, won the second annual Nestlï¿½ Smarties Book Prize and the 1987 Tir na n-Og Award as the year's best original-English-language book with "authentic Welsh background". The Stone Mouse was highly commended for the 1993 Carnegie Medal.