During my years at Columbia, I had many outstanding teachers in contemporary civilization, economics, and psychology, which was my undergrad co-major (with economics) and the concentration for my M.A. and Ph.D.

In psychology, Clarence Graham, Nat Schoenfeld, Connie Mueller, Bill McGill, and Fred Keller were there during my golden years. Among them, Fred Keller had the greatest influence on me: in my college years, as my professor for Introductory Psychology and later for a senior seminar; during my graduate studies, as a model scientist; after I myself became a psychology professor using his "Personalized System of Instruction," as a counselor-at-large; and later, as a management consultant to my business.

Part of his strong influence was because of his career's longevity--Fred lived to be 97. However, he also influenced me because of his remarkable personal qualities: his sense of humor, genuine approachability and modesty given remarkable scientific discoveries and professional awards, and most important, his abiding concern for students and the true purpose of teaching--his students' mastery of subject matter.

A legion of graduate and undergraduate students would say the same; I hope I'm only the first to tell you.