Despite its important role as a link between ancient and medieval philosophy, Plotinus' work is relatively little known among contemporary philosophers. This situation, however, is rapidly changing. Interest in later Greek philosophy has been growing steadily over the last decade, and work on Plotinus is flourishing. This major study brings Plotinus into the contemporary philosophical discussion. Lloyd P. Gerson gives a detailed account of Plotinus' arguments in the major philosophical areas of metaphysics, epistemology, psychology, and ethics. He examines the work of Plotinus both in its historical context and in its sustained systematic rigour. Focusing on Plotinus' defence of Platonism against Aristotle and on the development of Neoplatonism, Gerson reconstructs a powerful and systematic account of reality that is surprisingly relevant to modern debates.