Professor Charles Kittredge ran in long, unsteady strides. He was in time to bat the glass from the lips of Associate

Professor Heber Vandermeer. It was almost like an exercise in slow motion.

Vandermeer, whose absorption had apparently been such that he had not heard the thud of Kittredge's approach, looked at once startled and ashamed. His glance sank to the smashed glass and the puddling liquid that surrounded it.

"Potassium cyanide. I'd kept a bit, when we left. Just."m case...

"How would that have helped? And it's one glass gone, too. Now it's got to be cleaned up...No, I'll do it."

Kittredge found a precious fragment of cardboard to scoop up the glass fragments and an even more precious scrap of cloth to soak up the poisonous fluid. He left to discard the glass and, regretfully, the cardboard and cloth into one of the chutes that would puff them to the surface, a half mile up.

He returned to find Vandermeer sitting on the cot, eyes fixed glassily on the wall. The physicist's hair had turned quite white and he had lost weight, of course. There were no fat men in the Refuge. Kittredge, who had been long, thin, and gray to begin with, had, in contrast, scarcely changed.

Vandermeer said, "Remember the old days, Kitt."

"I try not to."

"It's the only pleasure left," said Vandermeer. "Schools were schools. There were classes, equipment, students, air, light, and people. People."

" A school's a school as long as there is one teacher and one student."

"You're almost right," mourned Vandermeer. "There are two teachers. You, chemistry. I, physics. The two of us, everything else we can get out of the books. And onegraduate student. He'll be the first man ever to get his Ph.D. down here. Quite a distinction. Poor Jones."

Kittredge put his hands behind his back to keep them steady. "There are twenty other youngsters who will live to be graduate students someday."

Vandermeer looked up. His face was gray. "What do we teach them meanwhile? History? How man discovered what makes hydrogen go boom and was happy as a lark while it went boom and boom and boom? Geography? We can describe how the winds blew the shining dust everywhere and the water currents carried the dissolved isotopes to all the deeps and shallows of the ocean."

Kittredge found it very hard. He and Vandermeer were the only qualified scientists who got away in time. The responsibility of the existence of a hundred men, women, and children was theirs as they hid from the dangers and rigors of the surface and from the terror Man had created here in this bubble of life half a mile below the planet's crust.

Desperately, he tried to put nerve into Vandermeer. He said, as forcefully as he could, "You know what we must teach them. We must keep science alive so that someday we can repopulate the Earth. Make a new start."

Vandermeer did not answer that. He turned his face to the wall.

Kittredge said, "Why not? Even radioactivity doesn't last forever. Let it take a thousand years, five thousand. Someday the radiation level on Earth's surface will drop to bearable amounts."

"Someday."

"Of course. Someday. Don't you see that what we have here is the most important school in the history of man? If we succeed, you and I, our descendants will have open sky and free-running water again. They'll even have," and he smiled wryly, "graduate schools such as those we remember."

Vandermeer said. "I don't believe any of it. At first, when it seemed better than dying, I would have believed anything. But now, it just doesn't make sense. So we'll teach them all we know, down here, and then we die... down here."

"But before long I ones will be teaching with us, and then there'll be others. The youngsters who hardly remember the old ways will become teachers, and then the youngsters who were born here will teach. This will be the critical point. Once the native-born are in charge, there will be no memories to destroy morale. This will be their life and they will have a goal to strive for, something to fight for...a whole world to win once more. If, Van, if we keep alive the knowledge of physical science on the graduate level. You understand why, don't you?"

"Of course I understand," said Vandermeer irritably, "but that doesn't make it possible."

"Giving up will make it impossible. That's for sure."

"Well. I'll try," said Vandermeer in a whisper.

So Kittredge moved to his own cot and closed his eves and wished desperately that he might be standing in hisprotective suit on the planet's surface. Just for a little while. Just for a little while. He would stand beside the shell of the ship that had been dismantled and cannibalized to create the bubble of life here below. Then he could rouse his own courage just after sunset by looking up and seeing; once more, just once more as it gleamed through the thin, cold atmosphere of Mars, the bright, dead evening star that was Earth.

***

Some people accuse me of getting every last bit of mileage out of everything I write. It's not a deliberate policy of mine, actually, but I must admit that the mileage does seem to mount up. Even as long ago as 1954 it was happening.

I had written LET'S NOT for my school, and, of course, I was not paid for it and didn't expect to be. Shortly thereafter, though, Martin Greenberg of Gnome Press asked me for an introduction for a new anthology he was planning, All A bout the Future, which was slated for publication in 1955.

I did not really like to refuse because I liked Martin Greenberg, even though he was years behind in his royalty payments. On the other hand, I did not wish to reward him with more material, so I compromised.

"How about a little story instead?" I said, and offered him LET'S NOT. He ran it as one of the introductions (the other, a more conventional one, was by Robert A. Heinlein) and, wonder of wonders, paid me ten dollars.

In that same year another turning point was hitting me. (Odd how many turning points there are in one's life, and how difficult it is to recognize them when they come.)

I had been writing nonfiction to a small extent ever since the days of my doctoral dissertation. There were scientific papers dealing with my research, for instance. These were not many, because I was not long in finding out that I was not really an enthusiastic researcher. Then, too, writing the papers was a dreadful chore, since scientific writing is abhorrently stylized and places a premium on poor quality.

The textbook was more enjoyable but in writing it I had been constantly hampered and tied down because of my two collaborators-wonderful men, both, but with styles different from my own. My frustration led me to a desire to write a biochemistry book on my own, not for medical students but for the general public. I looked upon it as only a dream, however, for I could not really see past my own science fiction.

However, my collaborator, Bill Boyd, had written a popular book on genetics, Genetics and the Races of Man (Little-Brown, 1950), and in 1953 there came from New York one Henry Schuman, owner of a small publishing house named after himself. He tried to persuade Bill to write a book for him but Bill was busy and, being a kindhearted soul, tried to let Mr. Schuman down easily by introducing him to me, with the suggestion that he get me to write a book.

Of course, I agreed and wrote the book promptly. When publication time rolled around, however, Henry Schuman had sold his firm to another small firm, Abelard. When my book appeared, then, it was THE CHEMICALS OF LIFE (Abelard-Schuman, 1954).

It was the first nonfiction hook that ever appeared with my name on it and no other; the first nonfiction book I ever wrote for the general public.

What's more, it had turned out to be a very easy task, much easier than my science fiction. I took only ten weeks to write the book, never spending more than an hour or two a day on it, and it was intense fun. I instantly began to think of other, similar nonfiction books I could do, and that began a course of action that was to fill my life-though I did not have any inkling at the time that this would happen.

That same year, too, it began to look as though a second offspring was on its way. This one also caught us by surprise and created a serious problem.

When we had first moved into our Waltham apartment, in the spring of 1951, there were just the two of us. We slept in one bedroom, and the other bedroom was the office. My book THE CURRENTS OF SPACE (Doubleday, 1952) was written in that second bedroom.

After David was born and grew large enough to need a room of his own, he got the second bedroom and my office was moved into the master bedroom, and that's where THE CAVES OF STEEL (Doubleday. 1953) was written.

Then, on February 19, 1955, my daughter, Robyn Joan, was born, and I moved into the corridor in anticipation. It was the only place left to me. The fourth of my Lucky Start novels was begun on the very day she was brought home from the hospital. It was LUCKY STARR AND THE BIG SUN OF MERCURY (Doubleday, 1956) and it was dedicated "To Robyn Joan, who did her best to interfere."

The interfering was entirely too efficient. With a child in each bedroom and me in the corridor it was bad enough, but eventually Robyn Joan would be large enough to need a room of her own, so we made up our mind to look for a house.

That was traumatic. I had never lived in a house. For all my thirty-five years of life, I had lived in a series of rented apartments. What had to be, however, had to be. In January 1956 we found a house in Newton, Massachusetts, just west of Boston, and on March 12, 1956, we moved in.

On March 16, 1956, Boston had one of its worst blizzards in memory, and three feet of snow fell. Having never had to shovel snow before, I found myself starting with a lulu in a deep, broad driveway. I had barely dug myself out when, on March 20, 1956, a second blizzard struck and four more feet fell.

The melting snow packed against the outer walls of the house found its way past the wood and into the basement and we had a small flood. -Heavens, how we wished ourselves back in the apartment.

But we survived that, and then came a graver worry for me at least. My life had changed so radically, what with two children, a house, and a mortgage, that I began to wonder if I would still be able to write. (My novel THE NAKED SUN, Doubleday, 1957, had been finished two days

before the move.) You know, one gets such a feeling that a writer is a delicate plant who must be carefully nurtured or he will wither, that any traumatic change in one's way of life is bound to give the feeling of all the blossoms being lopped off.

What with the blizzards and the snow-shoveling and the basement pumping and everything else, I didn't get a chance to try to write for a while.

But then Bob Lowndes asked me to do a story for Future, and in June 1956 I began my first writing job in the new house. It was the first heat wave of the season but the basement was cool, so I set up my typewriter there in the unique luxury of being able to feel cool in a heat wave.

There was no trouble. I could still write. I turned out EACH AN EXPLORER and it appeared in issue #30 of Future (the issues of this magazine were so irregular at this time that it was not felt safe to put a month-designation on the issues).