One of the main goals of this book is to determine if, in the works of some of the key authors in the history of Italian political philosophy, a notion of efficacy can be found. In legal philosophy, efficacy is the capacity a norm has to effectively influence citizens behavior. The principle of efficacy is that according to which an order or rule exists as such when it is followed effectively in practice. Here by efficacy I mean the idea that normative phenomena are self-justifying, without reference to extrinsic systems of value (such as natural law). The examinations of several texts undertaken here constitute reflections on this theme, without any claim to systematicity. They have been grouped together, roughly in historical order, by their common respect for the contexts within which they reason and reach decisions, which lends them a characteristic flavor of harsh realism that at times relies on a minimalist use of traditional normative categories. The second theme that emerges through the respective chapters (each of which constitutes the text for a lesson in a course for Ph.D. students) is that of the relationship between equality and vulnerability. Here the idea is to elaborate a concept of vulnerability that is not underpinned by what we in Italy call an anthropology, that is, a fixed notion of human nature. Instead this concept should be comprehensible and graspable solely on the basis of the recognition of decisions and actions that are merely efficacious, that function for what they are, and what they do. This recognition doesnt even need to be explicitly articulated by these authors with any specific, deliberately conscious awareness. The goal is not to identify a precise tradition of thought, one which elaborates a given line of reflection, but rather to highlight certain themes that emerge in the texts examined, even as the authors write with and for their own specific,contingent set of motives, which differ from time to time and place to place. These authors include some who are widely known, such as Dante, Machiavelli, and Beccaria. At times they are figures who typify certain key historical episodes, such as the Risorgimento (Giuseppe Mazzini) or Fascism (Cesare Lombroso and Santi Romano), while others reflect certain aspects of a contemporary debate (Pasolini and the Braibanti affair). The book is based on lectures given for a 2021 Ph.D. Course at the University of California, Berkeleys Department of Italian Studies.