This lecture discusses how Thomas Aquinas adapted Aristotelian thought and philosophical method to the needs of the Christian philosophy and theology of his time. It presents six aspects of the Aristotelian legacy that Aquinas integrated into his system: logic, epistemology, teleology, motion, politics, and legal thinking. An understanding of Thomas's social background and institutional context—the Dominican Order and the discourse of the university—helps us grasp Aquinas's significance for his time and ours.