"How? I don't understand."

"How did Mutt save Bigman? When the dog came running up past us, Bigman was somewhere under the ice, nowhere to be seen. Yet Mutt plunged in, made for Bigman without hesitation, and dragged him out. We accepted that without thought because we somehow expect dogs to find what can't be seen through their sense of smell. But Mutt's head was enclosed. He could neither see nor smell Bigman, yet had no trouble locating him. We ought to have seen that unusual sense perception was involved. We'll find out exactly which when our roboticists work over the carcass."

"Now that you explain," said Panner, "it looks plain enough. The dog had to give itself away because First Law compelled it not to allow a human being to come to harm."

"That's right," said Lucky. "Once suspicions of Mutt finally penetrated, a few other things started falling into place. Summers had maneuvered Norrich on board, yes, but in doing so, he also got Mutt on board. Moreover, Summers was the one who got Mutt for Norrich in the first place. The chances are that there is a spy ring on Earth whose only task is to distribute these robot dogs to people working in or near critical research centers.

"Dogs are perfect spies. If you find a dog nosing through your papers or walking through a super-secret section of a laboratory, are you concerned? Chances are you pet the dog and feed him a dog biscuit. I checked through Mutt as best I could and I think he has a built-in subetheric transmitter which keeps him in contact with his Sirian masters. They can see what he sees, hear what he hears. For instance, they saw the V-frog through Mutt's eyes, recognized its danger, and directed him to kill it. He could be made to handle an energy projector with which to fuse the lock of a door. Even if he was caught in the act, there was a good chance we would put it all down to the accidental happenings of a dog playing with a weapon he had found.

"But once all this had occurred to me, I was only at the beginning of the practical problem. I had to try to take the dog intact. I was sure that any obvious suspicion of Mutt would trigger an explosion inside him. So first I brought Norrich and Mutt to a safe distance from the ship by suggesting we dig Summers' grave. In that way if Mutt did explode, the ship, at least, and its men would escape. Naturally I left a note with Commander Donahue, to be opened in case I did not return, so that Earth would at least investigate dogs in research centers.

"I then accused Norrich…"

Bigman broke in, "Sands of Mars, Lucky, for a while I thought you really meant it when you said Norrich had killed the V-frog and fooled us with built-in emotion."

Lucky shook his head. "No, Bigman. If he could fool us with built-in emotion, why bother to kill the V-frog? No, I was making sure that if Sirians were listening through Mutt's senses, they would be convinced I was on the wrong track. In addition, I was setting up a situation for Mutt's benefit.

"You see, Bigman, under instructions, attacked Norrich. As a Seeing Eye dog, Mutt was built with strong orders to defend his master against attack, and obedience to orders are Second Law. Usually there's no problem here. Few people attack a blind man and those who do will usually stop if the dog simply growls and bares its fangs.

"But Bigman persisted in his attack, and Mutt, for the first time since being built, had to carry through all the way. But how could he? He couldn't hurt Big-man. First Law. Yet he couldn't allow Norrich to be hurt either. It was a complete dilemma and Mutt went out of commission. Once that happened, I gambled that any bomb he contained could no longer be triggered. So I removed it and after that we were safe."

Panner took a deep breath. "Very neat."

Lucky snorted. "Neat? I could have done this the first day I landed on Jupiter Nine, if I had my wits about me. I almost had it, at that. The thought was at the edge of my mind constantly and I never caught it."

Bigman said, "What was it, Lucky? I still don't know."

"It was simple enough. The V-frog detected animal emotion as well as human emotion. We had an example of that when we first landed on Jupiter Nine. We detected hunger in the mind of a cat. Then, later, we met Norrich and he urged you to aim a blow at him in order to show off Mutt's protectiveness. You did so. I detected Norrich's emotions and yours, Bigman, through the V-frog, but although Mutt showed every outward sign of anger, I detected no trace of such an emotion. There was the absolute proof as early as that, that Mutt had no emotions and was therefore no dog but a robot. Yet I was so convinced that I was looking for some human that my mind refused to see that point… Well, let's go to dinner and visit Norrich on the way. I want to promise him that we'll get him another dog, a real one."

They arose, and Bigman said, "Anyway, Lucky, maybe it took some time, but we've stopped the Sirians."

Lucky said quietly, "I don't know that we've stopped them, but certainly we've slowed them down."

About The Author

Isaac Asimov was born in the Soviet Union to his great surprise. He moved quickly to correct the situation. When his parents emigrated to the United States, Isaac (three years old at the time) stowed away in their baggage.' He has been an American citizen since the age of eight.

Brought up in Brooklyn, and educated in its public schools, he eventually found his way to Columbia University and, over the protests of the school administration, managed to annex a series of degrees in chemistry, up to and including a Ph.D. He then infiltrated Boston University and climbed the academic ladder, ignoring all cries of outrage, until he found himself Professor of Biochemistry.

Meanwhile, at the age of nine, he found the love of his life (in the inanimate sense) when he discovered his first science-fiction magazine. By the time he was eleven, be began to write stories, and at eighteen, he actually worked up the nerve to submit one. It was rejected. After four long months of tribulation and suffering, he sold his first story and, thereafter, he never looked back.

In 1941, when he was twenty-one years old, he wrote the classic short story' "Nightfall" and his future was assured. Shortly before that he had begun writing his robot stories, and shortly after that he had begun his Foundation series.

What was left except quantity? At the present time, he has published over 260 books, distributed through every major division of the Dewey system of library classification, and shows no signs of slowing up. He remains as youthful, as lively, and as lovable as ever, and grows more handsome with each year. You can be sure that this is so since he has written this little essay himself and his devotion to absolute objectivity is notorious.

He is married to Janet Jeppson, psychiatrist and writer, has two children by a previous marriage, and lives in New York City.