The aim of this book is to find an answer to the question: how did St. Thomas Aquinas (1224/5 - 1274) use Holy Scripture in his theology? Distinguishing between a quantitative method for determining the place of Scripture in a theological text, and a qualitative method for determining its functions, the author of this study concludes that Aquinas does not only use Scripture in several functions in his theology, but first and foremost regards Scripture as source and framework of theology itself. While an analysis of Aquinas' texts on the resurrection of Christ shows the functioning of Scripture as a factor within the text, but also as a precondition for the text, a series of comparisons between different subject matters, literary genres and sources show that the importance of Scripture is a characteristic of Aquinas' theology in its entirety, even at places where Scripture is not quoted at all. This conclusion does not only show the ecumenical importance of Aquinas' theology, but also the relevance of his theological manner of reading Scripture for modern theologians.