There is nobody in life, myth or literature quite like Paul Erdos. Perhaps Johnny Appleseed comes closest. Johnny loved apple trees more than anything else and travelled the country back and forth planting apple trees wherever he passed. Erdos was something like that. He wandered around the world planting mathematics wherever he went. His life was completely devoted to mathematics. He never married. He carried a small cardboard suitcase in which he kept his belongings (they only half filled the suitcase) his many friends took care of him. Possessions embarrassed him. On occasion he would be paid for a lecture or win some prize - but the money always went to some young couple who needed to pay off a mortgage - or to establish prizes for the solution of mathematical problems. He inspired thousands of young mathematicians to outdo themselves. And his name appears high on the short list of the best mathematicians in the twentieth century. But for me Erdos' impact was not on Mathematics at all but was on ethics. I first met Erdos the day that the atomic bomb was dropped on Hiroshima. I worked in the ballistic research laboratory at that time. Among my colleagues were several world class mathematicians (one was a corporal and another was a sergeant). They were, of course, Erdos' friends and they were regular stops in his world travels. When we heard the news about the atomic bomb a great shout went up and we rushed to the roof of the laboratory to celebrate. I was delighted because the fantasy of atomic power had come true, because the war was now over and I would be able to go back to school, and because the Japs got what was coming to them. To my surprise Erdos, who was always so cheerful, pointed out that there was much to mourn. We had placed incredible power in the hands of people who could not understand it and who would use it only for conquest. Many civilians had been killed. The horror of Hiroshima did not erase the horror of Pearl Harbor. On the contrary the effect was additive. He pointed out that we could have demonstrated the power of the bomb on an unoccupied island. He was very persuasive. And he has guided my thinking on many topics since that day. Sometimes in person, sometimes I just ask myself "what would Erdos think of that." Among other things I have learned that the pleasures of achievement, and just of making things grow, far outweigh the pleasure of acquisition. Paul Erdos, 83, died of a heart attack in Poland while attending a Mathematics Conference.