This 1967 study of Plotinus' philosophy was the first comprehensive work in English since Inge's The Philosophy of Plotinus was published early in the twentieth century. After a brief biography of Plotinus, Professor Rist discusses, among other topics, Plotinus' concept of the one, the logos and free will and ends with a discussion of faith in Plotinus and later in Neoplatonism. Perhaps because he is strictly neither a classical nor a medieval philosopher Plotinus' work has been rather neglected in the English-speaking world. Professor Rist has rescued him from this relative obscurity and has indicated some of the ways in which he has influenced both Christian and non-Christian philosophers.