Richard Pryor harnessed his comic genius in the mid-'70s, but in less than a decade his gifts were diminished by illness and excess. His peak came and went too quickly, and it took some years of hard work for him to find his voice and to shape the raw material that would be the backbone of his best material. As Pryor honed his craft, black America – bursting with anger, hope, and frustration – was changing too, as the civil rights movement gave way to the black liberation struggle. In this context, Pryor charged ahead into a world where increasingly anything seemed possible. His gift was to find humor in the ignorance and hypocrisy that flouted America's racial divide; he could expose Nixon as a small-minded liar as easily as he'd turn a vicious club-wielding cop into a bumbling ignoramus. And if his sketches were sometimes vulgar, he could get serious in a heartbeat, as he did to close the brilliant 1976 album Bicentennial Nigger, when he vowed, "But I ain't never gonna forget."

Anyone who saw Pryor before '75 will certainly remember the growing pains he underwent. Evolution/Revolution: The Early Years (1966-1974) shows Pryor planting the seeds of the future, trying out material at small comedy clubs before audiences that would occasionally challenge him and his jokes. Helping to define him later were bits like "Peoria" (about his hometown and his sometimes fractured family), "Whorehouse" (it's rumored that he grew up in one, which might explain this: "Is it really good, dear?" "Oh yeah, no white man ever fucked me like you, baby"), "The President" ("President Nixon's gonna do a lot for black people; he's gonna teach me to tap-dance"), and "I Spy Cops," a dig at Bill Cosby and his soft, salt-and-pepper cop show ("Cops are dangerous," he explained). And there's homophobic stupidity that eventually was less central to his work but never disappeared.

Is this Pryor's best work? Not by a long shot. But compared to much of what passed for comedy then and now, it's solid. More than that, it's a fascinating look at a man who during the 1970s played a crucial role in keeping America's racial conscience alive. On Evolution/Revolution, Pryor was all over the map, but he brought his heart and soul with him as he traveled – that's reason enough to pick up this album. (J.H. Tompkins)