In my mind's eye I still see Bob Clayton as he was first introduced to me by Sam Epstein, nodding hello from behind an extraction line at Caltech [the California Institute of Technology in Pasadena], where he was a graduate student. After getting his degree in chemistry, Bob went to Penn State [Pennsylvania State University, University Park] for 2 years but was lured to Chicago in 1958 when Harold Urey “retired.” Bob is exceedingly conscientious and more dedicated to excellence in science than anyone I know, and he awed those who may have expected a replacement for Urey by striding along his own new and clearly blazed trails. But Bob does the very best job possible in everything he does; in research, in teaching, in administration, and in service activities, and I'm glad I won't be around to worry about the void he leaves at retirement. Incidentally, I find it awkward in his presence to say anything good about him. He does not engage in small talk and unnecessary speculation and does not express subjective opinions; I fear he will challenge these Clayton-directed judgments as subjective, irrespective of their laudatory nature.