In a desperate move to make something of his life, an obscure physicist named Marshall Zebatinsky follows a hare-brained suggestion of his wife’s and consults a peculiar numerologist. The numerologist suggests he change his last name to "Sebatinsky"—and the change succeeds in ways Zebatinsky/Sebatinsky could never have dreamed.

This delightful little story is the result of Asimov spending most of his life having to correct the inevitable misspellings of his surname. As is common, the twist at the end is entirely unexpected, as it’s revealed that Zebatinsky has been the pawn of a bet of universal proportions. Meanwhile, the "butterfly effect" of the one name change is carefully and plausibly plotted out to its own surprising climax.