Abstract: This book is the first study that presents, in a single volume, the whole of St Maximus the Confessor's thought in the light of unity and diversity. The principle of simultaneous union and distinction forms the core of Maximus’ thought, pervading every area of his theology, and it can be summarized thus: things united remain distinct and without confusion in an inseparable union. The study is divided into five parts. Part I introduces the logical tools and metaphors of Maximian thought. Parts II and III examine the way in which Maximus views unity and difference in the Trinity and in Christ. The distinction between the universal and the particular, expressed in terms of essence (or nature) and hypostasis (or person), proves fundamental for a correct interpretation. Maximus’ dyophysite Christology includes topics on natural difference and number, composite hypostasis, enhypostaton, will, and activity, and it culminates in the notions of ‘union without confusion’ and ‘perichoresis’. Part IV highlights questions of unity and difference in the universe, Scripture, and the Church. God is the principle of unity behind the multiplicity and there is a dynamic in a perspective of eschatological fulfilment, from and through the multiplicity of the visible things to the unity of the invisible. Part V discusses Maximus’ spirituality of the twofold love for God and neighbour, and how this influences the unity (or disunity) of humanity.

Keywords: Byzantine theology, Trinity, Christology, hypostasis, monotheletism, Logoi, universe, Church, Scripture, spirituality