Jonas Mekas, sometimes called the godfather of the avant-garde cinema, actually dislikes documentary, because he feels the genre pretends to divulge everything about a subject. Still, the 85-year-old does not object to being filmed in the dusty Anthology Film Archives in New York, which he established in 1970. The packed storehouse is a fantastic treasure trove for lovers of the experimental film. The excitement of a young Italian, writing a paper on Harry Smith, when he comes face to face with a huge stack of film reels by his idol is contagious. Especially when he and a staff member start unpacking the psychedelic animation Mahagonny that was believed lost. We do not get to know everything about him and the experimental film genre, but this documentary, also related in form, is intriguing enough to make us want to.