The doctrine of the transcendentals is a prominent feature of medieval thought. Briefly stated, this doctrine asserts that "being" has certain properties, including unity, truth and goodness. One of Thomas Aquinas's contributions to reflection on the transcendentals was to articulate a set of transcendental properties relating "being" to the faculties of the soul: truth is "being" in relation to intellect and goodness is "being" in relation to will. Thus, truth and goodness are known as the relational transcendentals. ;As properties of (...) "being," the relational transcendentals are of obvious importance for metaphysics, and Thomas's modern interpreters have tended to treat them as an ontological issue separated from other philosophical and theological concerns. Thomas's most salient statements about truth and goodness suggest, however, that he constructed the relational transcendentals as part of a larger account that unites ontology, anthropology, ethics and theology. The goal of this dissertation is to reintegrate the relational transcendentals into that account. ;In order to provide a sense of how the modern tradition has regarded Thomas's statements about the relational transcendentals, I begin the dissertation with a survey of twentieth century studies on the topic. I then offer a detailed exegesis and commentary on the two texts that have provided the bases for most studies of the transcendentals in St. Thomas's thought: articles 1.1 and 21.1 of his Disputed Questions on Truth. Being careful to locate both texts within the larger discussions of their respective questions and, ultimately, within the context of the entire disputation, I argue that Thomas dwells on truth and goodness in them precisely as objects of the faculties of intellect and will. His discussions of the relational transcendentals are, thus, propadeutic to more extended psychological considerations of the human and divine intellects and wills. I conclude the dissertation by using this holistic account of the relational transcendentals and their psychological functions to reveal beauty as a third relational transcendental nestled between truth and goodness. (shrink)