The Vanishing Man by the late British author Sydney J. Bounds (
ISFDB,
Wikipedia,
SFE) is his vintage standalone science fiction adventure with espionage thriller elements, starring a man on an undercover mission to Mars, where the colonists seem to have nefarious plans to attack Earth, of which his attempts to investigate lead him to a strange and terrible case, free for a limited time courtesy of publisher Endeavour Press' Venture imprint.
This was originally published in 1953 by Hamilton & Co. under the title
Dimension of Horror.
Currently free @
Amazon (available to Canadians & in the UK and pretty much everywhere else Amazon sells worldwide, since this is being done via their KDP Select exclusive-or-else program)
Description
Alec Black, popular novelist and secret agent, had been sent on an undercover mission to Mars.
The Martian colonists were making preparations for a major offensive against Earth. Someone was working up a war-fever amongst them, and unless he could do something to prevent it, the whole system would be engulfed in atomic war.
Beginning his investigation, Black finds himself being shadowed by the driver of a car, a small, nondescript man in a grey suit. Crossing to the parked vehicle to confront the man, Black finds himself looking inside an empty car: the man had apparently vanished into thin air!
So began Black’s strangest case, one that was to plunge him into a dimension of horror...