"But, as I said once before, this is something many of us should have thought of. How is it you did?... Now we've gone into your background a little. Your co-worker, Ching, tells us you have hinted in the past at some serious danger involved in our probability-pattern setup, and that you insisted on going out to meet the Germans although you were obviously frightened. You were anticipating what you actually found, were you not? And how did you do it?"

Mishnoff said confusedly, "No, no. That was not in my mind at all. It came as a surprise. I-"

Suddenly he stiffened. Why not now? They were grateful to him. He had proved that he was a man to be taken into account. One unexpected thing had already happened.

He said firmly, "There's something else."

"Yes?"

(How did one begin?) "There's no life in the Solar System other than the life on Earth."

"That's right," said Berg benevolently.

"And computation has it that the probability of developing any form of interstellar travel is so low as to be infinitesimal."

"What are you getting at?"

"That all this is so in this probability! But there must be some probability patterns in which other life does exist in the Solar System or in which interstellar drives are developed by dwellers in other star systems."

Berg frowned. "Theoretically."

"In one of these probabilities, Earth may be visited by such intelligences. If it were a probability pattern in which Earth is inhabited, it won't affect us; they'll have no connection with us in Earth proper. But if it were a probability pattern in which Earth is uninhabited and they set up some sort of a base, they may find, by happenstance, one of our dwelling places."

"Why ours?" demanded Berg dryly. "What not a dwelling place of the Germans, for instance?"

"Because we spot our dwellings one to a world. The German Earth doesn't. Probably very few others do. The odds are in favor of us by billions to one. And if extraterrestrials do find such a dwelling, they'll investigate and find the route to Earth proper, a highly developed, rich world."

"Not if we turn off the twisting place," said Berg.

"Once they know that twisting places exist, they can construct their own," said Mishnoff. "A race intelligent enough to travel through space could do that, and from the equipment in the dwelling they would take over, they could easily spot our particular probability... And then how would we handle extraterrestrials? They're not Germans, or other Earths. They would have alien psychologies and motivations. And we're not even on our guard. We just keep setting up more and more worlds and increasing the chance every day that-"

His voice had risen in excitement and Berg shouted at him, "Nonsense. This is all ridiculous-"

The buzzer sounded and the communiplate brightened and showed the face of Ching. Ching's voice said, "I'm sorry to interrupt, but-"

"What is it?" demanded Berg savagely.

"There's a man here I don't know what to do with. He's drunk or crazy. He complains that his home is surrounded and that there are things staring through the glass roof of his garden."

"Things?" cried Mishnoff.

"Purple things with big red veins, three eyes and some sort of tentacles instead of hair. They have-"

But Mishnoff and Berg didn't hear the rest. They were staring at each other in sick horror.

The Message

They drank beer and reminisced as men will who have met after long separation. They called to mind the days under fire. They remembered sergeants and girls, both with exaggeration. Deadly things became humorous in retrospect, and trifles disregarded for ten years were hauled out for airing.

Including, of course, the perennial mystery.

"How do you account for it?" asked the first. "Who started it?"

The second shrugged. "No one started it. Everyone was doing it, like a disease. You, too, I suppose."

The first chuckled.

The third one said softly, "I never saw the fun in it. Maybe because I came across it first when I was under fire for the first time. North Africa."

"Really?" said the second.

"The first night on the beaches of Oran. I was getting under cover, making for some native shack and I saw it in the light of a flare-"

George was deliriously happy. Two years of red tape and now he was finally back in the past. Now he could complete his paper on the social life of the foot soldier of World War II with some authentic details.

Out of the warless, insipid society of the thirtieth century, he found himself for one glorious moment in the tense, superlative drama of the warlike twentieth.

North Africa! Site of the first great sea-borne invasion of the war! How the temporal physicists had scanned the area for the perfect spot and moment. This shadow of an empty wooden building was it. No human would approach for a known number of minutes. No blast would seriously affect it in that time. By being there, George would not affect history. He would be that ideal of the temporal physicist, the "pure observer."

It was even more terrific than he had imagined. There was the perpetual roar of artillery, the unseen tearing of planes overhead. There were the periodic lines of tracer bullets splitting the sky and the occasional ghastly glow of a flare twisting downward.

And he was here! He, George, was part of the war, part of an intense kind of life forever gone from the world of the thirtieth century, grown tame and gentle.

He imagined he could see the shadows of an advancing column of soldiers, hear the low cautious monosyllables slip from one to another. How he longed to be one of them in truth, not merely a momentary intruder, a "pure observer."

He stopped his note taking and stared at his stylus, its micro-light hypnotizing him for a moment. A sudden idea had overwhelmed him and he looked at the wood against which his shoulder pressed. This moment must not pass unforgotten into history. Surely doing this would affect nothing. He would use the older English dialect and there would be no suspicion.

He did it quickly and then spied a soldier running desperately toward the structure, dodging a burst of bullets. George knew his time was up, and, even as he knew it, found himself back in the thirtieth century.

It didn't matter. For those few minutes he had been part of World War II. A small part, but part. And others would know it. They might not know they knew it, but someone perhaps would repeat the message to himself.

Someone, perhaps that man running for shelter, would read it and know that along with all the heroes of the twentieth century was the "pure observer," the man from the thirtieth century, George Kilroy. He was there!

Satisfaction Guaranteed

Tony was tall and darkly handsome, with an incredibly patrician air drawn into every line of his unchangeable expression, and Claire Belmont regarded him through the crack in the door with a mixture of horror and dismay.

"I can't, Larry. I just can't have him in the house." Feverishly, she was searching her paralyzed mind for a stronger way of putting it; some way that would make sense and settle things, but she could only end with a simple repetition.

"Well, I can't!"

Larry Belmont regarded his wife stiffly, and there was that spark of impatience in his eyes that Claire hated to see, since she felt her own incompetence mirrored in it. "We're committed, Claire," he said, "and I can't have you backing out now. The company is sending me to Washington on this basis, and it probably means a promotion. It's perfectly safe and you know it. What's your objection?"

She frowned helplessly. "It just gives me the chills. I couldn't bear him."

"He's as human as you or I, almost. So, no nonsense. Come, get out there."

His hand was in the small of her back, shoving; and she found herself in her own living room, shivering. It was there, looking at her with a precise politeness, as though appraising his hostess-to-be of the next three weeks. Dr. Susan Calvin was there, too, sitting stiffly in thin-lipped abstraction. She had the cold, faraway look of someone who has worked with machines so long that a little of the steel had entered the blood.

"Hello," crackled Claire in general, and ineffectual, greeting.

But Larry was busily saving the situation with a spurious gaiety. "Here, Claire, I want you to meet Tony, a swell guy. This is my wife, Claire, Tony, old boy." Larry's hand draped itself amiably over Tony's shoulder, but Tony remained unresponsive and expressionless under the pressure.

He said, "How do you do, Mrs. Belmont."

And Claire jumped at Tony's voice. It was deep and mellow, smooth as the hair on his head or the skin on his face.

Before she could stop herself, she said, "Oh, my-you talk."

"Why not? Did you expect that I didn't?"

But Claire could only smile weakly. She didn't really know what she had expected. She looked away, then let him slide gently into the comer of her eye. His hair was smooth and black, like polished plastic-or was it really composed of separate hairs? And was the even, olive skin of his hands and face continued on past the obscurement of his formally cut clothing?

She was lost in the shuddering wonder of it, and had to force her thoughts back into place to meet Dr. Calvin's flat, unemotional voice.

"Mrs. Belmont, I hope you appreciate the importance of this experiment. Your husband tells me he has given you some of the background. I would like to give you more, as the senior psychologist of the U.S. Robots and Mechanical Men Corporation.

"Tony is a robot. His actual designation on the company files is TN-3, but he will answer to Tony. He is not a mechanical monster, nor simply a calculating machine of the type that were developed during World War II, fifty years ago. He has an artificial brain nearly as complicated as our own. It is an immense telephone switchboard on an atomic scale, so that billions of possible 'telephone connections' can be compressed into an instrument that will fit inside a skull.

"Such brains are manufactured for each model of robot specifically. Each contains a precalculated set of connections so that each robot knows the English language to start with and enough of anything else that may be necessary to perform his job.

"Until now, U.S. Robots has confined its manufacturing activity to industrial models for use in places where human labor is impractical-in deep mines, for instance, or in underwater work. But we want to invade the city and the home. To do so, we must get the ordinary man and woman to accept these robots without fear. You understand that there is nothing to fear."

"There isn't, Claire," interposed Larry earnestly. "Take my word for it. It's impossible for him to do any harm. You know I wouldn't leave him with you otherwise."

Claire cast a quick, secret glance at Tony and lowered her voice. "What if I make him angry?"

"You needn't whisper," said Dr. Calvin calmly. "He can't get angry with you, my dear. I told you that the switchboard connections of his brain were predetermined. Well, the most important connection of all is what we call The First Law of Robotics,' and it is merely this: 'No robot can harm a human being, or, through inaction, allow a human being to come to harm.' All robots are built so. No robot can be forced in any way to do harm to any human. So, you see, we need you and Tony as a preliminary experiment for our own guidance, while your husband is in Washington to arrange for government-supervised legal tests."

"You mean all this isn't legal?"

Larry cleared his throat. "Not just yet, but it's all right. He won't leave the house, and you mustn't let anyone see him. That's all... And, Claire, I'd stay with you, but I know too much about the robots. We must have a completely inexperienced tester so that we can have severe conditions. It's necessary."

"Oh, well," muttered Claire. Then, as a thought struck her, "But what does he do?"

"Housework," said Dr. Calvin shortly.

She got up to leave, and it was Larry who saw her to the front door. Claire stayed behind drearily. She caught a glimpse of herself in the mirror above the mantelpiece, and looked away hastily. She was very tired of her small, mousy face and her dim, unimaginative hair. Then she caught Tony's eyes upon her and almost smiled before she remembered...

He was only a machine.

Larry Belmont was on his way to the airport when he caught a glimpse of Gladys Claffern. She was the type of woman who seemed made to be seen in glimpses... Perfectly and precisely manufactured; dressed with thoughtful hand and eye; too gleaming to be stared at.

The little smile that preceded her and the faint scent that trailed her were a pair of beckoning fingers. Larry felt his stride break; he touched his hat, then hurried on.

As always he felt that vague anger. If Claire could only push her way into the Claffern clique, it would help so much. But what was the use.

Claire! The few times she had come face to face with Gladys, the little fool had been tongue-tied. He had no illusions. The testing of Tony was his big chance, and it was in Claire's hands. How much safer it would be in the hands of someone like Gladys Claffern.

Claire woke the second morning to the sound of a subdued knock on the bedroom door. Her mind clamored, then went icy. She had avoided Tony the first day, smiling thinly when she met him and brushing past with a wordless sound of apology.

"Is that you-Tony?"

"Yes, Mrs. Belmont. May I enter?"

She must have said yes, because he was in the room, quite suddenly and noiselessly. Her eyes and nose were simultaneously aware of the tray he was carrying.

"Breakfast?" she said.

"If you please."

She wouldn't have dared to refuse, so she pushed herself slowly into a sitting position and received it: poached eggs, buttered toast, coffee.

"I have brought the sugar and cream separately," said Tony. "I expect to learn your preference with time, in this and in other things."

She waited.

Tony, standing there straight and pliant as a metal rule, asked, after a moment, "Would you prefer to eat in privacy?"

"Yes... I mean, if you don't mind."

"Will you need help later in dressing?"

"Oh, my, no!" She clutched frantically at the sheet, so that the coffee hovered at the edge of catastrophe. She remained so, in rigor, then sank helplessly back against the pillow when the door closed him out of her sight again.

She got through breakfast somehow... He was only a machine, and if it were only more visible that he were it wouldn't be so frightening. Or if his expression would change. It just stayed there, nailed on. You couldn't tell what went on behind those dark eyes and that smooth, olive skin-stuff. The coffee cup beat a faint castanet for a moment as she set it back, empty, on the tray.

Then she realized that she had forgotten to add the sugar and cream after all, and she did so hate black coffee.

She burned a straight path from bedroom to kitchen after dressing. It was her house, after all, and there wasn't anything frippy about her, but she liked her kitchen clean. He should have waited for supervision...

But when she entered, she found a kitchen that might have been minted fire-new from the factory the moment before. v

She stopped, stared, turned on her heel and nearly ran into Tony. She yelped.

"May I help?" he asked.

"Tony," and she scraped the anger off the edges of her mind's panic, "you must make some noise when you walk. I can't have you stalking me, you know... Didn't you use this kitchen?"

"I did, Mrs. Belmont."

"It doesn't look it."

"I cleaned up afterward. Isn't that customary?"

Claire opened her eyes wide. After all, what could one say to that. She opened the oven compartment that held the pots, took a quick, unseeing look at the metallic glitter inside, then said with a tremor, "Very good. Quite satisfactory."

If at the moment, he had beamed; if he had smiled; if he had quirked the corner of his mouth the slightest bit, she felt that she could have warmed to him. But he remained an English lord in repose, as he said, "Thank you, Mrs. Belmont. Would you come into the living room?"