 In 1958 he was made a member of Harvard's prestigious Society of Fellows.He was assistant professor for several years at Princeton University, without, however, having finished his doctoral thesis, a study of the modern Chinese poet and literary figure, Guo Moruo.Professor Fairbank, at Princeton to give a talk, visited David in his office, spied the manuscript on his desk, took it in hand, and while leaving, congratulated David on having completed his Ph.D. degree.