Professor Frankfurt, who was emeritus at Princeton University, also taught for many years at Yale University and, before that, at Rockefeller University and Ohio State University. Early in his career, he wrote an influential book on Descartes, but was of course best-known in philosophy for seminal papers on free will. The NYT obituary is here. Comments are open for remembrances from those who knew Professor Frankfurt or for those who wish to comment on the significance of his work. Please submit your comment only once, they may take awhile to appear.