Daniel A. Keating presents a comprehensive account of sanctification and divinization in Cyril. By establishing the importance of pneumatology in Cyril's narrative of salvation and by showing the requirement for an ethical aspect of divinization grounded in the example of Christ himself, this study brings a corrective to certain readings of Cyril that tend to exaggerate the 'somatic' or 'physicalistic' character of his understanding of divinization. Keating argues that Cyril correlates the somatic and pneumatic means of our union with Christ, and integrates impressively the ontological and ethical aspects of our sanctification and divinization. A final chapter compares these findings with Theodore of Mopsuestia, Augustine, and Leo the Great, in order to examine in brief the relationship between Eastern and Western accounts of salvation.