In this seminal and classic work, Jean Daniélou examines the spiritual or mystical theology of St Gregory of Nyssa and its relationship to non-Christian, especially Platonic, thought. He strikes a balanced view, asserting that Gregory's vision is fundamentally Christian, though he articulates himself in Platonic terminology and categories. In fact, Nyssen turns many classical Greek notions on their head, and posits a dynamic and inspiring vision of the spiritual life as an infinite pursuit of the infinite God.