Director Michael Wadleigh’s tribute to love and redemption through lifestyle is a nostalgia piece now, but still fun: the film is fascinating, ear splitting, and screen splitting. Everyone is there, from Jimi Hendrix to Joan Baez. And there are a few, like Arlo Guthrie, who never left. Wadleigh’s documentary attitude wavers between acute observation and facile sociology, but his performance footage remains among the best ever filmed. (The director’s cut version, running close to four hours, includes about 40 additional minutes of Canned Heat, Jimi Hendrix, Janis Joplin, and the Jefferson Airplane.)