"Good Lord!" exclaimed Professor Harvey Beale, Craig's oldest associate, "why did you have to turn Ohm into such a grinning monster? I think I preferred him as a blank nonentity."

Craig laughed. "He is ferocious looking, isn't he? I devised that head to scare away peddlers and tramps. Now, when the doorbell rings and I don't want to be disturbed, I just let Ohm face them down!"

Professor Beale joined in Craig's laughter, but there was a note of constraint in his voice. "You feel that you have perfect control over Ohm?"

"Complete." Craig looked across the room where the robot basked in a puddle of yellow lamplight. "It's a wonderful feeling, Beale ... a feeling that you can never experience with a human being ... or even a cat or a dog."

With a little grunt, Ohm began moving toward the chair in which Craig sat. The single eye glistened in the leering face and the small wheels made a singing noise as he spun across the carpet.

Professor Beale followed the movement with some little apprehension. "What's such a wonderful feeling?"

Craig gestured to Ohm. "This sense of possession ... of control. It's a thing we all want ... every human being ... from the time we're old enough to clutch our first pet until we drop into our graves. We seek it in marriage ... in our children ... but we're always cheated, Beale. Always cheated because there's an unpredictable element. But with Ohm," he dropped his hand over the side of his easy chair and patted the metal head, "with Ohm, there's no doubt. No question. He's mine ... and no matter how sorely I try him, I can always predict his reactions."

Professor Beale nodded slowly. "I suppose. How ... how sorely have you tried him, Craig?"

"I haven't really put him to the test as yet. But now that the preliminaries are out of the way, I mean to begin. I'm going to thwart him, Beale. I'm going to frustrate him in every way. I'm going to deprive him of the thing he desires most ... light ... and observe his reactions."

A flicker of apprehension touched Beale's long, friendly face. "These experiments ... you'll do them at the school lab?"