Paul Olum was another friend who was among the smartest people on the planet. He was Provost and then President of the University of Oregon. In the latter position we joked that he was my boss as President and I was his as Head of the Department of Mathematics. He was an incredible leader.  When he told a faculty me meeting that we would get NO raises but explained what an important and honorable profession we were in, we all stood and applauded.  He could also easily and informally get along with anyone. He and his wife were also outstandingly moral people.

Again I plagiarize from Wikipedia (one of my greatest friends):

Born in Binghamton, New York to a father who was a Russian Jew who immigrated at age of nine to escape persecution, Olum took an interest in mathematics at an early age. He graduated summa cum laude from Harvard University in 1940. In 1942 he married Vivian Goldstein, completed an MA in physics at Princeton University, and joined the scientific staff of the Manhattan Project. During his time at Los Alamos, Olum was among the Los Alamos scientists who questioned the implications of the atomic bomb, and after its use against Japan, he became a lifelong advocate for world peace and for nuclear arms control.[1][2]

Reportedly, one reason he switched from Physics to Mathematics as his field was that compared to his office mate, future Nobel laureate Richard Feynman, Olum did not think he was good at Physics.[3] He returned to Harvard after the war to complete his PhD in Mathematics in 1947 under Hassler Whitney as his thesis advisor. Among his close friends was Feynman, who wrote in his autobiography of Paul’s intelligence. In one anecdote, Feynman told of an experience at Los Alamos when he had claimed to be able to take any problem that could be stated in ten seconds and find an answer to within ten percent in no more than sixty seconds. When Feynman made this challenge to Olum, he quickly responded, “Find the tangent of 10 to the 100th.”

“Surely You’re Joking, Mr. Feynman” is a wonderfully interesting book, but one of its purposes was to show how much smarter Richard Feynman (whom I never knew) was than just about everyone else.  Paul is the only person in the book who is treated as an equal or superior intellect.