The Sins of the Cities of the Plain purports to be the memoirs of Jack Saul, a young rentboy or "Mary-Ann". In the book Saul is picked up on the street by a Mr. Chambon. After they have dinner, Chambon invites Saul to recount his life story.

While some have accepted it as a genuine account, it is more likely to be an early form of the non-fiction novel. John Saul was an actual male prostitute of Irish birth, known as 'Dublin Jack', who was involved in a homosexual scandal at Dublin Castle in 1884, and later in the Cleveland Street scandal. The book is clearly inspired by him, and it is possible he shared his experiences with the anonymous author(s). Factual details suggest the book could be based on an authentic rentboy's account, but one that has been elaborated. There are consistencies with the real life Saul, but also discrepancies: he was of Irish birth, but in the book he is English.

Pornographic bookseller Charles Hirsch claimed that this was one of the "Socratic" books that he purveyed to Oscar Wilde in 1890.