This dissertation examines the role of the screen encounter in non-fiction films. “Screen encounter” is the term I use to name the phenomenon of seeing oneself onscreen. I argue that the screen encounter is not only a reception practice, but a device employed by the medium of cinema itself to bring aspects of the world into cinematic life. As a device within the world of a film, the screen encounter comes into being through images of social actors seeing themselves on-screen. Yet, the effects of this viewing experience primarily manifest through post-screening phenomena—testimonies, dialogues, debates, and conversations—when the film features its subjects reflecting on the see-yourself experience. This post-screening reflection emerges as a practice akin to the film forum, a pre-planned platform that transforms the individual film experience into a public dialogue and collective activity. The screen encounter thus establishes the film forum as a stage for film subjects to actively engage in reciprocal and collaborative processes of self-discovery and understanding. Despite its relevance throughout the history of non-fiction filmmaking, the device of the screen encounter has nonetheless been repeatedly overlooked in film scholarship, in part because it has fallen under broad discourses about self-reflexivity. This dissertation isolates the particularity of the screen encounter—the encounter with one’s literal self onscreen—from the larger history of cinema’s exploration of its mediating processes of reception. I argue that, once placed within the history of film theory, the screen encounter emerges as one of the means through which cinema grants the viewer a conscious relationship with history. Drawing from films from different geographies and historical periods, I examine how non-fiction filmmakers have mobilized the screen encounter to make social and political claims about a film’s subjects and the historical world in which they reside. This dissertation is comprised by three chapters. Chapter 1, “The Critique of the Screen Encounter,” gives an account of the screen encounter as an ethnographic device. By referencing cinema’s reception instead of cinema’s recording infrastructure, the ethnographic use of the screen encounter reconsiders the way participatory documentary has been historically understood. Chapter 2, “Aging Onscreen,” studies the role of the screen encounter in “documentary film sequels,” understood here as films that follow up on the lives of social actors documented in previous films. Far from being just a new label, the concept of documentary film sequel reshapes some of the debates surrounding cinema and aging by shifting the focus from questions of representation within a single film to the temporal relations established across films. Finally, Chapter 3, “Group Reassembling,” assesses the role of the screen encounter in the history of leftist political filmmaking. It argues that the screen encounter’s reception context has been used to restore a sense of belonging within a dispersed collectivity or group. With these case studies, this dissertation not only identifies and traces the device of the screen encounter, but it also offers critical frameworks for enriching and challenging the reflection of a phenomenon that informs and shapes our current lives.