“His normally gentle demeanor and ironic banter hid a violent temper and a harshly self-critical streak. When challenged in some unexpected fashion, he could become hysterical, literally vibrating and shaking with furry. His perfectionism, which would later prevent him from publishing a large portion of his research, was extreme. He was, moreover, acutely self-conscious about being a few years older than some of the brilliant young men around the Princeton mathematics department.”