Among the great works of Thomas Aquinas, the ""Commentary on the Sentences of Peter Lombard"" has suffered almost total neglect among translators. Such neglect is surprising, considering that the massive Commentary - more than 4,000 pages in the last printed edition - is not only Aquinas' first systematic engagement with all the philosophical and theological topics on which he expended his energy over the span of a short career but is also characterized by an exuberance and elaborateness seldom found in his subsequent writings. Although Chenu had already drawn attention decades ago to the importance of studying this youthful tour de force for a fuller understanding of Thomas' more mature work, the ""Commentary on the Sentences"" has remained a closed book for many modern students of Thomistic and medieval thought because of its relative inaccessibility in English or in Latin.The present volume, containing all the major texts on love and charity, makes available what is by far the most extensive translation ever to be made from the Commentary with the added benefit that the better part of the translation is based on the (as yet unpublished) critical edition of the Leonine Commission. The collection of texts from all four books has a tight thematic coherence that makes it invaluable to students of Thomas' moral philosophy, moral theology, and philosophical theology. In addition, the inclusion of parallel texts from Aquinas' first (Parisian) Commentary as well as from his second (Roman) attempt at a commentary, the recently rediscovered ""Lectura Romana"", makes this edition all the more valuable for those who wish to track the internal development of Thomas' thinking on these matters.The new availability of so many rich passages from the ""Commentary on the Sentences"" will encourage and facilitate use of a magnificent resource that deserves to be better known.