The Secret Martians

Jery Delvin had a most unusual talent. He could detect the flaws in any scheme almost on sight—even where they had eluded the best brains in the ad agency where he worked. So when the Chief of World Security told him that he had been selected as the answer to the Solar System's greatest mystery, Jery assumed that it was because of his mental agility.
But when he got to Mars to find out why fifteen boys had vanished from a spaceship in mid-space, he found out that even his quick mind needed time to pierce the maze of out-of-this-world double-dealing. For Jery had become a walking bomb, and when he set himself off, it would be the end of the whole puzzle of THE SECRET MARTIANS—with Jery as the first to go!
Jack Sharkey decided to be a writer nineteen years ago, in the Fourth Grade, when he realized all at once that "someone wrote all those stories in the textbooks." While everyone else looked forward variously to becoming firemen, cowboys, and trapeze artists, Jack was devouring every book he could get his hands on, figuring that "if I put enough literature into my head, some of it might overflow and come out."
After sixteen years of education, Jack found himself teaching high school English in Chicago, a worthwhile career, but "not what one would call zesty." After a two-year Army hitch, and a year in advertising "sublimating my urge to write things for cash," Jack moved to New York, determined to make a career of full-time fiction-writing.
Oddly enough, it worked out, and he now does nothing else. He says, "I'd like to say I do this for fulfillment, or for cash, or because it's my destiny; however, the real reason (same as that expressed by Jean Kerr) is that this kind of stay-at-home self-employment lets me sleep late in the morning."