This work lays out the theoretical background to Saint Thomas Aquinas' spirituality. It shows that his theology is clearly oriented towards contemplation and is as deeply spiritual as it is doctrinal. The text quotes often from Thomas' own texts and presents a clear understanding of Aquinas' views on nature, the person, human society, politics, and our ultimate end in communion with God and one another. It makes apparent why the Catholic Church thinks of Aquinas not only as a great Christian intellectual, but also as a saint.