John "Steve" Stevenson (10 July 1930 – 27 November 2017) was a British writer who, under the pen name Marcus van Heller, wrote erotic fiction for the Traveller's Companion series of Olympia Press publisher (1955–1961).

[1] The main editor of Merlin, Alexander Trocchi, used to write erotic fiction for Olympia Press publisher to supplement his meagre income and suggested to Stevenson to do the same.

Olympia Press specialised in books which could not be published (without legal action) in the English-speaking world, making use of the fact that the French were more sexually tolerant and few were able to read in English.

[2] Continuing in the same vein, Roman Orgy (1956) presented an intimate account of the private life of the rebel leader Spartacus, and The House of Borgia, parts 1 and 2 (1957, 1958), a fictional biography of the 15th century Italian noble family with an emphasis on their considerable depravity.

"In the netherworld of erotica, the name Marcus van Heller approaches the stature of legend" (portrayal by John de St. Jorre in his book about the history of Olympia Press).

[6] This fact and also a negative remark from Girodias regarding the effort he put into writing his most recent novel determined Stevenson to end the collaboration with Olympia Press and return to Britain in 1961.