“He was too scared himself. He was shaking all over and when he saw me his eyes got even brighter, and he started to get up. He was trembling so I had to help him to his feet.
“I steadied him with one arm and lifted off the helmet with my free hand. As you know, you can stay outside a suit on the moon without getting frostbitten for about half a minute.
“When his face came into view and his eyes looked straight into mine I was so startled that fifteen seconds were lost right at the start—before a single word could be exchanged between us. But at least I had a chance to get a good look at him.
“If you saw yourself as a boy of ten, suddenly, without warning, would you recognize yourself? Maybe some men would. If you looked at yourself a lot in a mirror when you were growing up—or kept photographs of yourself, carefully preserved in an old album, you might not have any trouble. Right off you might hear yourself muttering, ‘Why, that’s me!’
“But I had trouble. The kid’s face was just enough like my own to give me a start. But I couldn’t really place it—couldn’t remember where I had seen it before.
“Then the kid spoke. ‘I—I thought you were Pops! But you’re not! He’s older! Where am I? How did I get here?’
“The voice did something to me. You get a chance to hear yourself talking a lot when you’re knee-high to a grasshopper. And I had no kids of my own! But my own father had looked enough like me to be my twin brother, and if this kid thought I was his dad—
“It hit me between the eyes—and like a voice screaming at me through a blur of spinning suns!
“I was staring at myself as I had been long ago—and no tracks made by a dead man in a bog could have been more nerve-shattering.
“He wasn’t even a poor little kid in a desperate plight, because you can’t feel paternal about yourself! He was a tormented ghost out of the past, and for an instant I had an impulse to blame him and rail at him for returning to torture me.
“But I’m not a cruel man, deep down, and that crazy impulse passed quickly. He was a poor little lost cuss, even if he was myself, and all my sympathy went out to him.
“I even forgot for a moment how insane the whole thing was. He was gasping for breath, so I put the helmet back on, and gave the oxygen tube a double twist to straighten it out. But an instant before the helmet descended over his mouth he managed to stammer, ‘I was up in the attic playing—’
“Playing ‘Pirate’s den!’ I had spent the happiest years of my boyhood in the attic, pretending I was Captain Kidd, or climbing out on the tree that arched over our house when the December snows weighed it down, and making myself out to be in the crow’s nest of an arctic windjammer!
“As I swayed there beside myself my mind followed crazy-paved paths in all directions. Great chunks of the past seemed to float before me—like icebergs nine-tenths submerged.
“But all the while the sanest part of my mind was seeking an explanation that would one-tenth explain it! I gripped my own boy-self by the shoulder to make sure he’d stay solid until the man he’d become could get a mental toehold on the problem.
“If you can persuade a man to mount a stepladder and plant himself firmly on the air you’ve taken your first brave step into the unknown. The poor devil may or may not fall. But at least you’ve made a start in the right direction.
“It isn’t too hard to believe that certain things can happen to Time on the wrong side of yesterday—or tomorrow! Time—the physicists tell us—never stops flowing. It’s like a melting candle or silk before it hardens on the loom—all crinkled up and sparkling like a dew-drenched spider web.
“If Time melts in a back-of-yesterday dimension what’s to stop a man from dissolving with it, and running in a thin trickle back to his yesterdays? You were a boy once and you could be a boy again—without ceasing to be a man.
“Put it this way. On the dark side of the moon there was a valley of shadows. A big, blundering fool went stumbling into it, and landed in a heap. Before he could pick himself up a part of himself dissolved in some unimaginable backwash of time, and he became a boy again. His boy-self split off from him, and went stumbling off over the plain in a suit five sizes too large for him.
“It’s not as impossible as it sounds. The boy you were still exists in Time, and he could emerge from the past to stand beside you in a vortex of dissolving Time. Was there something in the valley that could change the flow of time, reverse it, and twist it around like butter in a churn?
“The answer was right there in the cave with me. But I couldn’t see it because another spacesuited figure was making my brain whirl. He’d come clumping into the cave bent nearly double, and now he was shuffling toward me as though I’d committed some horrible crime I could never hope to atone for.
“Through the pane of his helmet his eyes burned accusingly into mine. But it wasn’t until he halted directly in front of me and lifted the helmet from his head that I knew what my crime was and why he found it hard to forgive me.
“I had committed the crime of living beyond my alloted span! The man facing me was old … old. His face was still my face, but if ever I had been young and handsome and a target for the wiles of a pretty woman I was so no longer!
“He seemed to realize that
