"Years ago, when I was an assistant professor of physics at Berkeley, I used to be invited down to Cal Tech about once a year to give a talk. It was usually the low point of my year. In the audience at Cal Tech were two leaders of modern physics, Murray Gell-Mann and Richard Feynman, who interrupted with frequent questions, ruthlessly probing to see if I really knew what I was talking about and had anything new to say. Of the two, Feynman was the more frightening. Gell-Mann was mostly interested in finding out whether there was anything in my talk that he should know about, so he was no problem if I did have anything worth while to say. Feynman was having fun. It is Feynman as a fun-lover - chum of Las Vegas showgirls, cracker of safes at Los Alamos, player of bongo drums - who has won the hearts of the public. I found this side of Feynman hard to take. But, of course, Feynman had a more serious side. He did not do his great work on the quantum theory of fields in a moment between bongo gigs, but over several years of hard intellectual labour. On a more personal level, while helping to design the atomic bomb at Los Alamos during the war, Feynman devotedly nursed his first wife through her tragic and ultimately fatal illness. And Feynman thought deeply about the goals and methods of science, as shown in his 1964 Messenger lectures at Cornell."