What a century of border films teaches about the real and imagined worlds of the US-Mexico borderlands--and how this understanding helps build better relations across boundaries. Border Witness is an account of cultural collision and fusion between Mexico and the United States, as seen on the ground and in films from the past hundred years. Blending film studies with political and cultural geography, Michael Dear investigates the making of cross-border identity and community in the territories between two nations. Border Witness introduces a new "border film" genre just now entering its golden age. A geographer and activist, Dear adopts an accessible and engaged perspective, combining the stories told by these films with insights drawn from his own decades-long research and travel. From early silent films to virtual reality, and from revolution to the present global crisis, border films provide fresh evidence for real and imagined politics and for envisioning future transborder architectures carved from in-between spaces. In an era of global geopolitics that favors walls and war over diplomacy, Dear's insights have relevance for borders around the world.