This introduction presents an overview of the contents discussed in the book and how the book is organized. The first Part of the book provides the complex story of the developments in Greek philosophy which led up to Plotinus, from Plato and Aristotle onwards. The second part focuses on Philo and the beginning of Christian thought, where authors find Jews and Christians taking over Greek ideas and adapting them to their own purposes and ways of thinking long before Plotinus. Third and fourth parts of the book deal with Plotinus himself and the story of pagan Neoplatonism to its end in the sixth century. The next two parts concerns exclusively with Christian thought and the story of Greek Christian Platonism from the fourth to the ninth century. Final part of the book gives a sketch of early Islamic philosophy.