And a little bone to pick, not with this story, but with Harry Turtledove, editor of The Best Alternate History Stories of the 20th Century, which includes this story. I suppose he’s just marketing the book with a title that he supposes will sell, but I would like a clear distinction drawn between alternate history (What if the South won the war?), time travel (such as this story), and true history (such as the true story of how Asimov met Campbell).