In this incisive study, John F. X. Knasas grounds the ideal of tolerance in Aquinas’s natural law ethics and connects the virtue of civic tolerance to the concept of being. If God is the source of being, argues Knasas, then we are the articulation of being, and it is in this capacity that we recognize our bond with other people and thus acknowledge our duty to be tolerant of one another. An important contribution to practical metaphysics and the philosophical foundations of political theory, Thomism and Tolerance will appeal to philosophy scholars and students at the undergraduate and graduate level.