This dissertation undertakes an analysis of Gregory of Nyssa's final work, In Canticum Canticorum. Part I investigates Gregory's earlier works. In Part II, Gregory's fifteen homilies on the Song of Songs are analysed in light of key structures of thought explored in Part I. Special emphasis is placed on Gregory's trinitarian theology, christology and pneumatology, as well as the relationship between 'doctrinal' and 'exegetical' works.