Steve Carradine is an agent with British Intelligence.
31 years old, tall and muscular with "the palest gray eyes which seemed to look through, and never at, anyone", Carradine has been an agent for just over three years as the documented portion of the series begins. He is a black belt in judo and an expert in karate. A natural talent with languages, he speaks several well and Spanish and Russian as a native.
The agency for which Carradine works is unnamed but is referred to as the least-known section of intelligence community for the United Kingdom, so secret in fact that Carradine did not know the true name of his boss, the head of the organization. In fact, he comments early on that he had never seen his boss outside the man's office. This short, chubby, balding man that directs Carradine and a handful of other agents cares for his people but is still curt and brusque when dealing with them.
The missions that Carradine is sent on are international in nature, taking him to North and South America, Asia, Europe, and Africa, fighting despots, Soviet agents, and the Red Chinese, as well as the occasional crime boss and femme fatale. In the relatively short time that he has been an agent, Carradine has managed to get a reputation with the other side. In one book the field leader of the opposition remarks that Carradine is a particularly dangerous man who has already caused their side considerable trouble. In another book Carradine comments to a lovely lady that "I've had to kill men in my time and I suppose that by the law of averages, there are those who have been ordered to kill me."