Students of St. Augustine might well assume that he identified restlessness exclusively with the impulses of the heart and the range of affectivities shaping human choices. But Augustine was also preoccupied with the dynamics of the restless mind prompted by curiosity. His extensive discussions of curiosity (which he identified with the "lust of the eyes" of Scripture) reveal a profound psychological discovery on his part, namely, the cognitive appetitiveness that provides the stimulus to our ongoing search for knowledge. This book explores the metaphysical, epistemological, and moral implications of curiosity in Augustine's writings, against the background of the classical, scriptural, and patristic traditions. In broader terms, it puts Augustine in conversation with later currents of thought, assessing how his deliberations on the curious disposition say something significant about the scope and limits of human inquiry, particularly in the context of scientific investigation.