This book presents a series of Dr. Blumenthal’s studies on the history of Neoplatonism, from its founder Plotinus to the end of Classical Antiquity, relating especially to the Neoplatonists’ doctrines about the soul. The work falls into two parts. The first deals with Plotinus and considers the soul both as part of the structure of the universe and in its capacity as the basis of the individual’s vital and cognitive functions. The second part is concerned with the later history of Neoplatonism, including its end. Its main focus is the investigation of how Neoplatonic psychology was modified and developed by later philosophers, in particular the commentators on Aristotle, and used as the starting point for their Platonizing interpretations of his philosophy.