This night, however, he was in unfamiliar territory: the Sheraton Commander in Cambridge, across Harvard Square, and he had really banged his knee. He was still rubbing it while sitting on the toilet, the sound of the last few pings of urine clearly audible in the silence. The pain had fully wakened him, and he began to think of the lecture. Suddenly it struck him. My God, he thought as he reached for the light switch, that's it! How could I've missed it? The light blinded him momentarily as he stretched for the robe hanging on the back of the door.

It was 3:14 A.M. when Professor I. Cantor sat at the small desk and started scribbling on the only piece of paper he could find in the desk drawer. It may have been the first time in history that a Nobel Prize-winning idea was set down on the back of a laundry list.