After resolving to become a Catholic Christian, Augustine spent a decade trying to clarify his understanding of 'contemplation,' the interior presence of God to the soul. That long struggle yielded his classic account in the Confessions. This study explores Augustine's developing understanding of contemplation, beginning with his earliest accounts written before his baptism and ending with the Confessions. Chapter One examines the pagan monotheism of the Roman Platonists and the role of contemplation in their theology. Augustine's pre-baptismal writings are then considered in Chapter Two, tracking his fundamental break from pagan Platonism. Chapter Three then turns to Augustine's developing understanding of contemplation in these pre-baptismal texts. Chapter Four concentrates on Augustine's thought during the decade after his baptism in 387, a period that encompasses his monastic life in Thagaste, and his years first as a presbyter and then as a bishop in Hippo Regius. This chapter follows the arc of Augustine's thought through these years of transition and leads into the Confessions, giving a vantage point to survey its theology of contemplation. Chapter Five concentrates on the Confessions and sets its most famous account of contemplation, the vision at Ostia from Book IX, into a larger polemical context. Augustine's defence of his transcendental reading of scripture in Confessions XII is analysed and then used to illuminate the Ostian ascent narrative. The book concludes with observations on the importance of Augustine's theology of contemplation to the emergence of Christian monotheism in late antiquity.