A short story by Alfred Bester, one of the great time travel stories. It originally appeared in the October 1958 issue of The Magazine of Fantasy and Science Fiction.

The thing that struck me the most was the tone of the story. Bester manages precisely the right amount of whimsey for this tale to work. Played straight, I don’t think it would have the same effect, and played as a pure farce, it would be just silly. The nature of the plot requires that amount of whimsey, as we shall see. Spoilers ahead!

Bester spends a page and a half discussing anecdotes of famous scientific geniuses who did rather strange things. “Now, these men weren’t idiots. They were geniuses who paid a high price for their genius because the rest of their thinking was other-world.” But this is not an unrelated digression or superfluous, because it makes what happens next utterly believable, and without that seemingly irrelevant opening, the rest might seem too silly to be swallowed by the reader.

He then introduces one of those geniuses, Henry Hassel, a professor in the far flung future of 1980. (Give him a break, it was 1958, after all.) Hassel returns to find his beautiful wife in the arms of another man. Instead of simply killing her, as a man of lesser intellect might, he plans to utterly eliminate her existence. And the best way to do that is a time machine, which he whips up in his home laboratory in seven and a half minutes. (Told you it was whimsical.)

He goes back in time to kill her grandfather. When he returns, she is still in that unfaithful embrace. He kills her grandmother, and she’s still there. Frustrated, he begins a spree of carnage throughout time, knocking off George Washington, Christopher Columbus, Napoleon, Mohammed, and plenty of others. She’s still there. He goes back in time to visit Marie Curie (this is a hysterical touch) and teaches her nuclear fission. Paris goes up in a mushroom cloud and she’s still there.

Throughout this process, Hassel is growing dim and insubstantial, which he finally realizes when his bullets fail to kill Enrico Fermi. To figure out what’s going on, he consults the foremost expert on time travel, who just happens to be a professor at his institution, Wiley Murphy. Professor Murphy also, conveniently enough, happens to be in the arms of his wife. In true geek fashion, he ignores the adultery and runs some equations by him. But he doesn’t hear him.

Hassel is interrupted by Israel Lennox, a time travel expert who disappeared in 1975. Lennox tells Hassel why he can’t change time, something he knows about because he tried the same thing. Bester avoids the traditional time travel clichés (he even, as an aside to the reader, quips earlier in the story that “I’d better warn you that this is not a conventional time story”) as he reveals why you can’t change history. Each person dwells in their own time continuum, and they can only travel up and down their own. The carnage each of the men affected on the past unhinged them from their continuums, so they dwell as insubstantial ghosts, voyeurs throughout time.