From the first time he had seen him, Thorn had tagged Sorensen as an Angry Old Man. Not that he was really getting old; he was still somewhere on the brisk side of fifty. But he wore a perpetual scowl on his face that looked as though it had been etched there by too many years of frustration, and his voice always seemed to have an acid edge to it, like that of an old man who has decided, after decades of observation, that all men are fools. And yet Thorn thought he occasionally caught a glimpse of mocking humor in the pale blue eyes. He was lean and rather tall, with white hair that still showed traces of blond, and he looked as Scandinavian as his name sounded. His accent was pure Minnesota American. As he climbed out of the jeep, Sorensen brought with him the Black Suitcase. Ever since he had first seen it, Thorn had thought of it as "the Black Suitcase," and after he had seen some of the preliminary tests, he had subconsciously put capitals to the words. But Richard Thorn was no fool. Too many men had been suckered before, and he, Richard Thorn, did not intend to be another sucker, no matter how impressed he might be by the performance of an invention. If this was a con game, it was going to have to be a good one to get by Richard Thorn, Ph.D. He walked across the few feet of hard, salt-white ground that separated him from Sorensen standing beside the second jeep with the Black Suitcase in his hand. It was obvious to anyone who watched the way Sorensen handled the thing that it was heavy--seventy-five pounds or better. "Need any help?" Thorn asked, knowing what the answer would be. "Nope," Sorensen said. "I can handle it." The suitcase wasn't really black. It was a dark cordovan brown, made even darker by long usage, which had added oily stains to the well-used leather. But Thorn thought of it as the Black Suitcase simply because it was the perfect example of the proverbial Little Black Box--the box that Did Things. As a test question in an examination, the Little Black Box performs a useful function. The examiner draws a symbolic electronic circuit. Somewhere in the circuit, instead of drawing the component that is supposed to be there, he draws a Little Black Box. Then he defines the wave-form, voltage, and amperage entering the circuit and defines whatever is coming out. Question: What is in the Little Black Box? Except in the simplest of cases, there is never an absolute answer. The question is counted as correct if the student puts into the Little Black Box a component or subcircuit which will produce the effect desired. The value of the answer depends on the simplicity and relative controllability of the component drawn in the place of the Little Black Box. Sorensen's Black Suitcase was still a problem to Thorn. He couldn't quite figure out what was in it.