The question of the identity of thought and being is central to Neoplatonism. Proclus is an extreme example of the dialectic of distinction and connection, the in-itself and the interrelation of the individual, the belonging together of identity and difference: both poles are to be seen both in themselves and simultaneously in their relational unity. This serves as a historical and factual reference point to the concept of concrete totality in Hegel, who regarded the metaphysics of Proclus as the culmination of Neoplatonism and thus as the pinnacle of ancient thought. This book clarifies the systematic density of Proclus's work and simultaneously traces philosophical historical connections both forward and backward. In this dual sense, the book sets standards for Neoplatonism research.