Henry J. Blumenthal was a leading British scholar in the area of Neoplatonism. From 1965 until his untimely death in 1998 he worked at the department of Greek Classics and Archaeology, University of Liverpool, starting out as lecturer in Greek, gaining full Professorship, and eventually becoming department Chair. He is the author of Plotinus' Psychology His Doctrines of the Embodied Soul, and Aristotle and Neoplatonism in Late Antiquity. Many of his articles, spanning over a quarter of a century, were gathered and published in the collection Soul and Intellect.

For Plotinus, the nature and status of the human soul is one of the central problems of philosophy. Ennead IV.3-4.29 constitutes his most penetrating enquiry into this topic, addressing the issues of the relation of the individual soul to the World Soul, the descent of the soul into body, its relations with that body, problems of personal identity and the nature of memory, sense perception, and the true seat of the emotions -many of which still have a resonance today. The treatise is an excellent example of Plotinus' distinctive method of enquiry: not dogmatic (though he is no sceptic), but worrying away at questions until he has uncovered their complexities to the best of his ability. Such a work requires detailed commentary, such as is provided here, to tease out fully the fascinating convolutions of his thought.