“TheBlackPowerMixtape1967-1975, ”amongotherthingsanextraordinaryfeatofeditingandarchivalresearch, takesupafamiliarperiodinAmericanhistoryfromafreshandfascinatingangle.Inthelate1960sandearly’70s, SwedishtelevisionjournaliststraveledtotheUnitedStateswiththeintentionof“showingthecountryasitreallyis.”So...