The Party Family, the title of my doctoral dissertation, encapsulates the multiple layers of this research on communist activism in twentieth-century Chile. First and foremost, this is a study of communist families, their internal dynamics and their private practices. Second, it is an invitation to think of communist parties as extended families, with networks of solidarity and hierarchical relationships based on gender and age. Finally, it is an attempt to engage with, and speak to, the larger audience of scholars interested in what political scientists call the family of communist parties. The research spans from the mid-1930s to 1973 and is based on four types of sources: the communist press, oral histories, civil registry documents, and internal party documentation. By studying Chilean communist families in the long duration and through a diverse set of sources, my research delves into the interpenetration of the public and the private spheres in political activism. "The first duty of a militant," the statutes of the party asserted, "is to make the acts of his or her public and private life fit the principles and program of the party." A communist was not only supposed to be a good revolutionary in the street, but also the best spouse and parent at home. I believe that a study of this dimension of Chilean communism can help advance a more holistic definition of political activism. Focusing on armed insurgency and state repression, scholars of Latin America have aptly argued that politics was a matter of life and death. I put the emphasis on everyday activism at home rather than intermittent violence in the streets to rethink politics as an existential matter in the broadest sense. Although centered on a specific communist party, informed by sociological questions, and rooted in historical methods, my dissertation seeks to challenge our understanding of what constitutes both politics and human beings as political animals.