Specialising in the fields of Black British history and literature, S. I. Martin works with museums, archives and the education sector to bring diverse histories to wider audiences. He has published five books of historical fiction and non-fiction for adult and teenage readers.

He founded the 500 Years of Black London walks nearly 20 years ago in response to the low profile given to the Black historical presence on the capital's streets. He has consistently encouraged and championed the provision of plaques, street names and street furniture to this end. He has worked with and for the Black Cultural Archives, National Maritime Museum, V&A, Tate Britain, London Metropolitan Archives, National Portrait Gallery, Horniman Museum, The National Archives, RAF Museum, Wellcome Trust and many others. He regularly provides workshops and sessions for heritage institutions, schools, borough councils and community groups across the country.