Ed Pincus was one of the founders of the MIT Film Section, a training ground for future documentary filmmakers like Ross McElwee. Pincus produced a body of work that straddles the line between the purported objectivity of Direct Cinema, a movement he helped pioneer with early works like the Black Natchez, and the more self-reflecting style known as personal documentary. As its name suggests, Diaries: 1971-1976 belongs in the latter category, an intimate epic that examines the inextricable Gordian knot of personal and political commitment by turning the camera eye on friends and family. Bookended by intimations of mortality, the deaths of a relative and close friend, Diaries spends most of its three-hour-plus run time charting the shifting sexual climate of the 1970s, delving into experiments in lifestyle choices ranging from nudism to open marriage. Frequent exchanges between Pincus and wife Jane, a member of the feminist collective responsible for the manifesto Our Bodies, Ourselves, consider the consequences of their decisions not only on their own relationship, but also on their two young children. Diaries also records, albeit in a distanced, Brechtian fashion, the last gasps of anti-war protest and the disintegration of the counterculture, at least the Cambridge variety. For a stretch late in the film, Diaries achieves a gritty kind of New Hollywood vibe as Pincus and a fellow filmmaker range around the desert Southwest, the documentary equivalent of Easy Rider. As a time capsule, Diaries is invaluable, but Pincus’s decision to work against narrative cohesion by cutting away from conversations at key moments, and otherwise hashing up individual segments, renders the film chaotic and disjointed, sapping it of the cumulative impact found in documentaries like Allan King’s A Married Couple, let alone the massive slab of social experimentation then going on over at PBS called An American Family.