"Karpo Sixteen predicted the possibility just the other day! Listen, my friend, let me ask you just a few questions--" Then the mechanical voice of the operator cut in. It wasn't a real operator, of course, just a recorded voice, part of the new automatic system. These voices gave all the standard phrases and usually at the wrong time, the way the system was working. The worst of it was you couldn't argue with them or curse them--at least you always felt a little foolish afterward if you did. The operator's voice said, "_I'm sorry. Your time is up!_" "Now, wait!" said my communicant, his voice fading a little, "Don't cut us off! Don't think off yet!" Again: "_I'm sorry. Your time is up!_" And after that a click, and after that silence. I jiggled the hook a few times. No result. I shrugged. I hung up and rearranged the papers on my desk and went back to work, forgetting for the moment the party I'd been trying to call in the first place. And forgetting the odd conversation I had just had. No--not quite. Not quite forgetting it. Queerly, it clung to my mind. What had he said his name was? Zon Twenty. Sounded like that, anyway. Odd name. Of course I still thought it was a gag of some kind. Yet it bothered me. Zon's manner, his tone of voice had been so convincing. What he had said suggested that in some queer way I had managed to place a telephone call into the future. But as a sane, normal, recently promoted colonel, I knew this was impossible. At lunch I was still thinking about it. I ate in the officers' mess on my floor and steered my tray through the line. I saw, among other acquaintances Major "Clipper" Moskowitz at a far table, and remembered that he was a great science fan, always talking about rockets and reaching the moon, and that sort of thing--we had one argument about why a rocket works in a vacuum, such as space, and he hammered the table and drew diagrams and quoted Newton, and I'm still not convinced. Anyway, I went over and sat next to Clipper. "'Lo, Larry. How's it?" he said. "Routine," I said. "Latest request for overseas duty turned down. I'll probably die in the Pentagon with my pencil still behind my ear." We talked of such things for several minutes. "Clipper," I said finally, "you're the G.L.E. on this future science stuff--" "The what?" "Greatest Living Expert. Latest Pentagonese. Tell me, what do you think of the possibility of ever being in touch with the future?" "You mean time travel?" "I guess that's what you'd call it." "Time travel is nonsense," he said. "A logical absurdity. By definition, time is a series of infinitesimally small moments in succession. Once a point in time is established, it can't be changed, any more than energy can be destroyed." "I didn't say anything about changing anything. I was thinking about--well, talking with somebody in the future."