In 1971 he taught a course on gay and lesbian literature at Florida State University, one of the earliest gay courses in the United States. He was an active member of the Gay Liberation Front from 1971-72, and was involved in campaigning for the repeal of Florida's sodomy statute.
Since 1973 he has lived in London, working as a journalist, publisher, researcher and freelance scholar. He worked as a research editor for Gay News from 1974 to 1978. He wrote articles on gay history and literature for publications such as Gay Sunshine and The Advocate throughout the 1970s, and for Gay Times later. In December 2005 he formed a civil partnership with his partner of nearly thirty years.
His book, Mother Clap's Molly House has been turned into a play by Mark Ravenhill.
- The Homosexual Literary Tradition: An Interpretation. New York: Revisionist Press, 1974.
- Mother Clap's Molly House: The Gay Subculture in England, 1700—1830. London: Gay Men’s Press, 1992. A second edition, revised and enlarged, was published by Chalfont Press (an imprint of Tempus Publishing, United Kingdom) on October 10, 2006.
- The Myth of the Modern Homosexual: Queer History and the Search for Cultural Unity. London: Cassell, 1997.
- (ed.) My Dear Boy: Gay Love Letters through the Centuries. Leyland Publications, San Francisco. 1998 ISBN 0-943595-71-1
- Mistress of Udolpho: The Life of Ann Radcliffe. London: Leicester University Press, 1999
- Gothic Readings: The First Wave, 1764-1840. London: Leicester University Press, 2000.
- (ed.) Sex Doctors and Sex Crimes: Vol 5 of Eighteenth-Century British Erotica Part I
- (ed.) Sodomites, Mollies, Sapphists & Tommies: Vol 5 of Eighteenth-Century British Erotica Part II