I am not having the robot stories appear in the order in which they were written. Rather, I am grouping them by the nature of the contents. In this first division, for instance, I deal with robots that have a non-human shape-a dog, an automobile, a box. Why not? The industrial robots that have come into existence in reality are non-human in appearance.

The very first story, "A Boy's Best Friend," is not in any of my earlier collections. It was written on September 10, 1974-and you may find in it a distant echo of "Robbie," written thirty-five years earlier, which appears later in this volume. Don't think I'm not aware of that.

You will note, by the way, that in these three stories, the concept of Robot-as-Pathos is clearly marked. You may also notice, however, that in "Sally" there seems to be no hint of the Three Laws and that there is more than a hint of Robot-as-Menace. Well, if I want to do that once in a while, I can, I suppose. Who's there to stop me?

Mr. Anderson said, "Where's Jimmy, dear?"

"Out on the crater," said Mrs. Anderson. "Hell be all right Robutt is with him.-Did he arrive?"

"Yes. He's at the rocket station, going through the tests. Actually, I can hardly wait to see him myself. I haven't really seen one since I left Earth 15 years ago. You can't count films."

"Jimmy has never seen one," said Mrs. Anderson.

"Because he's Moonborn and can't visit Earth. That's why I'm bringing one here. I think it's the first one ever on the Moon."

"It cost enough," said Mrs. Anderson, with a small sigh. "Maintaining Robutt isn't cheap, either," said Mr. Anderson.

Jimmy was out on the crater, as his mother had said. By Earth standards, he was spindly, but rather tall for a 10-year-old. His arms and legs were long and agile. He looked thicker and stubbier with his spacesuit on, but he could handle the lunar gravity as no Earth-born human being could. His father couldn't begin to keep up with him when Jimmy stretched his legs and went into the kangaroo hop.

The outer side of the crater sloped southward and the Earth, which was low in the southern sky (where it always was, as seen from Lunar City) was nearly full, so that the entire crater-slope was brightly lit

The slope was a gentle one and even the weight of the spacesuit couldn't keep Jimmy from racing up it in a floating hop that made the gravity seem nonexistent.

"Come on, Robutt," he shouted.

Robutt, who could hear him by radio, squeaked and bounded after.

Jimmy, expert though he was, couldn't outrace Robutt, who didn't need a spacesuit, and had four legs and tendons of steel. Robutt sailed over Jimmy's head, somersaulting and landing almost under his feet.

"Don't show off, Robutt," said Jimmy, "and stay in sight."

Robutt squeaked again, the special squeak that meant "Yes."

"I don't trust you, you faker," shouted Jimmy, and up he went in one last bound that carried him over the curved upper edge of the crater wall and down onto the inner slope.

The Earth sank below the top of the crater wall and at once it was pitch-dark around him. A warm, friendly darkness that wiped out the difference between ground and sky except for the glitter of stars.

Actually, Jimmy wasn't supposed to exercise along the dark side of the crater wall. The grown ups said it was dangerous, but that was because they were never there. The ground was smooth and crunchy and Jimmy knew the exact location of every one of the few rocks.

Besides, how could it be dangerous racing through the dark when Robutt was right there with him, bouncing around and squeaking and glowing? Even without the glow, Robutt could tell where he was, and where Jimmy was, by radar. Jimmy couldn't go wrong while Robutt was around, tripping him when he was too near a rock, or jumping on him to show how much he loved him, or circling around and squeaking low and scared when Jimmy hid behind a rock, when all the time Robutt knew well enough where he was. Once Jimmy had lain still and pretended he was hurt and Robutt had sounded the radio alarm and people from Lunar City got there in a hurry. Jimmy's father had let him hear about that little trick, and Jimmy never tried it again.

Just as he was remembering that, he heard his father's voice on his private wavelength. "Jimmy, come back. I have something to tell you."

Jimmy was out of his spacesuit now and washed up. You always had to wash up after coming in from outside. Even Robutt had to be sprayed, but he loved it. He stood there on all fours, his little foot-long body quivering and glowing just a tiny bit, and his small head, with no mouth, with two large glassed-in eyes, and with a bump where the brain was. He squeaked until Mr. Anderson said, "Quiet, Robutt."

Mr. Anderson was smiling. "We have something for you, Jimmy. It's at the rocket station now, but we'll have it tomorrow after all the tests are over. I thought I'd tell you now."

"From Earth, Dad?" "A dog from Earth, son. A real dog. A Scotch terrier puppy. The first dog on the Moon. You won't need Robutt any more. We can't keep them both, you know, and some other boy or girl will have Robutt." He seemed to be waiting for Jimmy to say something, then he said, "You know what a dog is, Jimmy. It's the real thing. Robutt's only a mechanical imitation, a robot-mutt. That's how he got his name."

Jimmy frowned. "Robutt isn't an imitation, Dad. He's my dog." "Not a real one, Jimmy. Robutt's just steel and wiring and a simple positronic brain. It's not alive."

"He does everything I want him to do, Dad. He understands me. Sure, he's alive."

"No, son. Robutt is just a machine. It's just programmed to act the way it does. A dog is alive. You won't want Robutt after you have the dog."

"The dog will need a spacesuit, won't he?" "Yes, of course. But it will be worth the money and he'll get used to it. And he won't need one in the City. You'll see the difference once he gets here."

Jimmy looked at Robutt, who was squeaking again, a very low, slow squeak, that seemed frightened. Jimmy held out his arms and Robutt was in them in one bound. Jimmy said, "What will the difference be between Robutt and the dog?"

"It's hard to explain," said Mr. Anderson, "but it will be easy to see. The dog will really love you. Robutt is just adjusted to act as though it loves you."

"But, Dad, we don't know what's inside the dog, or what his feelings are. Maybe it's just acting, too."

Mr. Anderson frowned. "Jimmy, you'll know the difference when you experience the love of a living thing."

Jimmy held Robutt tightly. He was frowning, too, and the desperate look on his face meant that he wouldn't change his mind. He said, "But what's the difference how they act? How about how I feel? I love Robutt and that's what counts."

And the little robot-mutt, which had never been held so tightly in all its existence, squeaked high and rapid squeaks-happy squeaks.