The date was August 1, 1941. World War II had been raging for two years. France had fallen, the Battle of Britain had been fought, and the Soviet Union had just been invaded by Nazi Germany. The bombing of Pearl Harbor was four months in the future. But on that day, with Europe in flames, and the evil shadow of Adolf Hitler apparently falling over all the world, what was chiefly on my mind was a meeting toward which I was hastening. I was 21 years old, a graduate student in chemistry at Columbia University, and I had been writing science fiction professionally for three years. In that time, I had sold five stories to John Campbell, editor of Astounding, and the fifth story, "Nightfall," was about to appear in the September 1941 issue of the magazine. I had an appointment to see Mr. Campbell to tell him the plot of a new story I was planning to write, and the catch was that I had no plot in mind, not the trace of one. I therefore tried a device I sometimes use. I opened a book at random and set up free association, beginning with whatever I first saw. The book I had with me was a collection of the Gilbert and Sullivan plays. I happened to open it to the picture of the Fairy Queen of lolanthe throwing herself at the feet of