This night, however, he was in unfamiliar territory: the Sheraton Commanderin 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 lastfew pings of urine clearly audible in the silence. The pain had fully wakenedhim, 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'vemissed it? The light blinded him momentarily as he stretched for the robehanging on the back of the door.

It was 3:14 A.M. when Professor I. Cantor sat at the small desk and startedscribbling 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 ideawas set down on the back of a laundry list.