The German philosopher Martin Heidegger is one of the most significant philosophers of the twentieth century, on the one hand because he attempts to receive the whole Western philosophical tradition that comes before him, through an interpretation of its essential sources, and on the other hand because he arguably sets the terms for a great deal of the “postmodern” thought that comes after him. Moreover, Heidegger is known for having, more than anyone else in the modern era, retrieved the great “question of being.” Because of his status as a pivotal figure in this respect, a proper assessment of his work is especially needed in Catholic thought. In this course, we will start by reading a selection of texts that locate Heidegger and his influence in Christian theology. Then, we will spend a significant part of the course reading Heidegger himself, especially in his later essays. And, finally, we will consider principal representatives of those in the Catholic tradition that have appropriated him with enthusiasm, criticized him in a complete way, and received some of his ideas in a critical spirit.