As for Mac, of course, he is the same as ever; the same polished silvery body, encased in the simple tunic I have made to cover his metallic nakedness. They are almost the same height, but Fitz is a bit taller, and growing each day. Before long, it will be time to reconstruct my robot child's body again.

I have presented my first full-length paper on the experiment to the National Robotics Society. I must admit that I eagerly await their acceptance and publication.

Sept. 3, 2003. This morning, I opened my door upon a matronly woman whose pleasantries concealed an icy attitude towards myself and my family. She introduced herself as Mrs. Margotson, chairwoman of the local school board.

It was some time before Mrs. Margotson revealed the true purpose of her visit, which was to expose the board's reluctance to accept the enrollment of Mac, my robot child.

"You understand, of course," she told me, "that there is no question concerning your son. But the idea of this machine entering our school is perfectly absurd."

I had written a lengthy letter which explained my experiment in detail, but it had made little impression upon the authorities. She kept referring to "that metal thing" and "that machine" and her lip curled in disgust. I wasn't too upset by her attitude; I rather expected it.

"I understand," I told her. "To be honest, I did not expect approval, but I felt it my duty to make the application. However, since the board refuses, I shall not enter either child. I will tutor them both at home."

Mrs. Margotson looked shocked. "Are you serious about this experiment, Dr. Keeley?"

"Certainly. They are brothers, you know."

"Really!"

Both Fitz and Mac were delighted with my plans for their education; it seemed that neither one was keen on the idea of entering the local school. I didn't find out exactly why until late that afternoon.

The reason became apparent when Mac and Fitz returned from some mysterious outing. There was a vacancy in Fitz's mouth where a tooth had been recently and forcibly removed. There was a faint bruise on his cheek, and a hole in the knee of his trousers. I was disturbed by this evidence of a brawl, but was even more shocked and surprised to see a large dent in Mac's silvery forehead. I knew he felt no physical pain, but it was startling.

"What happened?" I said.

Fitz, always the spokesman, shrugged his shoulders.

"Just a fight," he said glumly.

"What do you mean, just a fight? Who with? What about?"

"Some-kids. Kids from the school."

"How many kids?"

"Five or six," Fitz said. "They threw things. Rocks."

I was appalled, and now I knew what had caused the dent. I don't know why I should have been surprised at the tale of violence. I had learned before, in our old city neighborhood, that my robot child was a natural target for the cruel taunts and unthinking violence of children.

I treated Fitz's wounds, and then drew Mac aside. "What happened?" I asked gently. "Fitz told you. We had a fight."

"I want to hear your version. Were they making fun of you, Mac? Is that it?"

"Yes."

"How did you feel about it?" I asked the question eagerly; it was important to me to learn the emotional responses of my creation.

Mac didn't answer for a while, his face a silver mask.

"Did you feel hurt, angry? Did you want to strike back?

I've told you this often, Mac-you must never strike a human. They're soft, you know, not hard like you. Did you want to hurt them, Mac?" Instinctively, I reached for pencil and paper to record his reactions.

"Yes," he said.

My heart leaped. My robot child had felt anger!

"But you didn't?"

"No."

"Why, Mac? Because you realized you were strong and they were weak? Because they felt pain and you didn't?"

"No!" He was almost defiant.

"What, then?"

"Because I am little," he whispered.

The reply disturbed me. I hadn't yet gotten around to performing the mechanical surgery that would give Machine his new body. He was several inches shorter than his brother, shorter than most boys his age.

Patiently, I explained to him again the rules of conduct I expected of him, rules that could never be broken. There must be no harm to humans; it was the cardinal rule of our code.

"Do you understand that, Mac? Truly understand it?"

"Yes," he answered, his blank eyes on the floor. I sighed.

"All right, then. I will make you bigger, Mac. I will build a new body."

April 23, 2008. It feels good to be recognized, I must admit it. The award conferred upon me by the National Robotics Society yesterday has meant a great deal to me. It has made a difference in the attitude of my neighbors; they no longer think of me as a half-mad creator of monsters, a new Frankenstein. And the monetary grant, while not enormous, will permit me to expand my laboratory facilities. It has come at an opportune time; I have been blueprinting a greatly improved physical housing for Mac, one which will permit his metal body greater flexibility and digital dexterity. I think, too, that I can create a superior sound system for him now, which will overcome the flat, metallic voice of my robot child.

Both Mac and Fitz are not overly impressed by my sudden fame. But I believe Mac is secretly excited by my promise to build him a better body. He has become acutely aware of his appearance; I have caught him gazing (with what emotion, I cannot say) into the mirrors of the house, standing before them with a stillness that only a robot can maintain. I have questioned him at length about his feelings, but have learned little. I must be sure to keep close to his emotional growth.

But if I have a real source of happiness now, it is my son Fitz. He has become a fine handsome boy, of such good humor and intelligence that he is extremely popular with all the residents of the town-and the power of his engaging personality has created an acceptance for Mac, his robot brother, that all my elaborate scientific titles couldn't have attained. He is still fiercely loyal to Mac, but I already detect signs of independence. These do not worry me; they would be natural even among human brothers. Fitz is discovering that he is an individual; it's a process of life.

But I wonder-will Mac feel the same way?

Jan. 4, 2012. There has been a quarrel, and it has taken me several days to learn the true details. I have never been disturbed about quarrels between Fitz and Mac; they have had surprisingly few for brothers. But for the first time, I sensed that the quarrel concerned the differences between them.

It began last week, when a boy of their age, Philip, a hostile surly youth, involved Fitz in a fight.

Philip is the son of a divorced woman in the town, named Mrs. Stanton. She is a strange, brooding woman, with a terrible resentment against her ex-husband. I am afraid some of the resentment has been passed on to her son, Philip, and that he is an unhappy youngster. For the last two months, Fitz has been a frequent visitor to their home, and Mrs. Stanton has displayed great fondness for him. Philip, of course, doesn't like this affection, this stolen love, and has developed a strong animosity towards Fitz. One day, it turned into violence.

Philip is big for his fifteen years, a tall boy, well over six feet, and well muscled. When he stopped Fitz and Mac on the street that morning, it was immediately apparent that he was seeking trouble. Fitz is not afraid of him, I know that; but Fitz tries to laugh trouble away. But the boy was in no mood to be put off with a smile. He lashed out and knocked Fitz down. When he got to his feet, Philip knocked him down again, and then leaped atop him.

I don't know what outcome the fight would have had if Fitz had been allowed to finish it. But he didn't have the chance. Mac, who was standing by, watching the altercation in his blank manner, suddenly threw himself upon his brother's assailant and pulled him away as easily as if Philip had been an infant. He lifted him into the air with his superhuman strength and merely held him there. He didn't hurt Philip, he traded no blows; he simply held him, helpless, in the air, while the boy kicked and screamed his frustration and anger. Fitz shouted at his brother to release him, and eventually Mac did. Philip didn't resume the attack; he was frightened by the easy, unconquerable strength in Mac's metal arms. He turned and ran, shouting threats and ugly names over his shoulder.

Of course, I know Mac's intent was good. He was protecting his brother, and wasn't violating the code of conduct. But I can also understand Fitz's emotion. He didn't feel grateful for Mac's help, only resentful. He turned upon the robot and reviled him, called him terrible names I never knew were in his vocabulary. He told Mac that he didn't want protection, that he could fight his own battles, that he didn't require Mac's metal strength to keep him from harm. He said a great deal more, and it is well that Mac is not more sensitive than he is.

There is a strain between them now. For the last few days, Fitz has been leaving the house without Mac's company. Mac, fortunately, doesn't seem injured by his behavior. He sits, blank-faced as ever, in his room. He reads or listens to his phonograph. Sometimes, he gets up and stares into the mirror, for interminable periods.

Oct. 15, 2016. It is extraordinary, the speed with which Mac has learned his lessons. For the past year, I have been teaching him the secrets of his own construction, and how he himself could repair or improve all or part of his artificial body. He has been spending five or six hours each day in my laboratory workshop, and now I believe he is as skilled as-or perhaps more skilled than-I am myself. It will not be long before he blueprints and builds his own new body. No, not blueprint. I cannot allow him to design the plans, not yet. The Face episode proved that.

It began last Friday evening, when Fitz left the house to take Karen to the movies. As usual, Mac seemed lost without his brother, and sat quietly in his room. About midnight, he must have heard the sound of my typewriter in the study, because he came to the doorway. I invited him in and we chatted. He was curious about certain things, and asking a great number of questions about Karen. Not sex questions, particularly; Mac is as well read as any adult, and knows a good deal about human biology and human passions (I wonder sometimes what his opinion is of it all!) But he was interested in learning more about Fitz and Karen, about the nature of their relationship, the special kind of fondness Fitz seemed to display towards the girl.