Later stories were produced by G. T. Fleming-Roberts (born George Thomas Roberts, 1910-1968), Emile C. Tepperman (1899-1951) and Wayne Rogers (pen name of Archibald Bittner (1897-1966).

His weapon of choice was a gas gun which quickly rendered people unconscious for a short time without any side effects.

Although ostensibly in the crime genre, the Secret Agent X stories were situated at the more far-fetched end of the spectrum, with a number of science fiction elements such as futuristic weapons and mad scientists.

They were generally given highly sensational titles such as The Ambassador of Doom (May 1934), Servants of the Skull (November 1934), The Golden Ghoul (July 1935), Satan’s Syndicate (August 1937) and Curse of the Crimson Horde (September 1938).

[1] Archived 2012-11-02 at the Wayback Machine There were a number of similarities between Secret Agent X and other pulp heroes of the time such as The Shadow, the Green Lama and Operator No.

Ace Comics also published a short-lived character based on Secret Agent X, but called him "X- The Phantom Fed".

In the 1960s, at the height of the camp craze and the success of the Doc Savage reprints, Corinth Press (an imprint of soft porn publisher Regency) issued seven Secret Agent X adventures in paperback.

Stephen Payne wrote a fourth new Secret Agent X novel, The Resurrection Ring, which revealed new facts about the origin of the Man of a Thousand Faces.

Set in New Orleans in 1932, it showcases an adventure from before the Agent's recorded career, wherein the Man of a Thousand Faces battles the terrible Mister Seven, a variant of an ancient European legend.

Future tales will include a pair of Cold War adventures: Fear's Flotilla and Time of the Terrible People.

Age of Adventure published a full-length Secret Agent X novel set during World War II, The Sea Wraiths by Sean Ellis.