Debt has become a paramount topic of discussion and controversy in recent times, fuelled by the financial crisis of 2008 and the different episodes of the sovereign debt crisis in Europe, above all involving Greece. This has produced a great deal of commentaries, economic analyses, and journalistic polemics from all sides of the political spectrum. Yet despite this profusion of discourse, it still proves difficult to seize the exact contours of the problem. Debt affects both the most isolated individuals and the most powerful states, it is equally a matter of “cold” economic rationality and the “hottest” emotions and moral judgments, it appears at once as the most empirical thing with the hardest material consequences and as a mysterious, ethereal, abstract, and purely speculative entity (the unreal product of financial “speculation”). The concept of indebtedness not only characterizes an increasingly universal economic predicament, but also defines a form of subjectivity central to our present condition. This seminar will examine the problem of debt by first looking at how different approaches to it—economic, anthropological, and psychodynamic—were formed by Marx, Nietzsche, and Freud, and then reading more contemporary authors on the theme, including Deleuze and Guattari, Foucault, Graeber, and Lazzarato.