Bernard Lonergan's theological writings have influenced religious scholars ever since the first publication in the 1940s of the series of five articles which make up Verbum: Word and Idea in Aquinas. These articles first appeared in Theological Studies and were subsequently republished in book form in 1967 under the present title. This volume contains a new preface by the editors and full translations of all Latin texts. Verbum: Word and Idea in Aquinas is a product of Lonergan's eleven years of study of the thought of Thomas Aquinas. The work is considered by many to be a breakthrough in the history of Lonergan's theology and a foundation upon which his later contributions were constructed. Here he interprets aspects in the writing of Aquinas relevant to trinitarian theory and, as in most of Lonergan's work, one of the principal aims is to assist the reader in the search to understand the workings of the human mind. Verbum: Word and Idea in Aquinas is a vital component of Lonergan's oeuvre, and of continuing relevance to trinitarian theology, Aquinas studies, and inquiries into human cognition.