S.I. Martin is a writer and historian, founder of the series of narrative London walks entitled '500 Years of Black London'. He also works in education and the media, specialising in Black British history and literature. He is the author of an adult novel Incomparable World, and Britain's Slave Trade for the Channel 4 series of the same name. He is much in demand with English Heritage, National Maritime Museum, Museum of London, Museum in Docklands, Imperial War Museum and British Council Literature wing. Jupiter Williams, and the sequel, Jupiter Amidships, are his first children's books.