Questlove's Summer of Soul is an engaging, well-cut documentary about a series of Harlem Cultural Festival concerts held in Marcus Garvey Park during the mid to late summer of 1969. It's not my idea of a thematically unified, shoot-and-assemble "documentary" as much as a savoring of found footage -- footage that sat in a cellar for decades, and was finally restored and cut just right and punctuated with talking heads.