Patricio Guzmán’s career in documentary film now stretches through six decades. He started out as a young man filming on the streets a political movement and the challenges it faced, lived through a coup and subsequent arrest, then went into exile to Europe. There he made less urgent films, often for French or Spanish television, while frequently returning to Chile to film more politically engaged work. More recently he made a trilogy in essay mode that linked the past and present of his home…