Francisco Vitoria was the earliest and arguably the most important of the Thomist philosophers of the counter-Reformation. His works are of great importance for an understanding of both the rise of modern absolutism, and the debate about the emergent imperialism of the European powers, and are unusually accessible since they survive in the form of summaries of his lecture courses on law and theology. Translated here into English for the first time, these texts comprise the core of Vitoria's thought, and are accompanied by a comprehensive introduction, chronology, and bibliography.