It is not just that American religion was so diverse and complicated in the 1960s and 1970s that makes the challenge of addressing the subject so daunting; it is that this was an era, in American religion as elsewhere, where change, or at least turmoil, often reigned. Mark Oppenheimer admirably succeeds in meeting the challenge of explaining all this, and I applaud his Knocking on Heaven's Door. Oppenheimer considers change in five quite varied religious groups: the Unitarians, Roman Catholics, Jews, Southern Baptists, and Episcopalians. He focuses both on church institutional structures and on the attitudes and the practices of church members. He identifies a particular dimension for each group to mark the influence of the counterculture of the 1960s. With the Unitarians it was the movement toward embracing gays, with the Roman Catholics the arrival of the folk mass, with the Jews the rise of extradenomina-tional religious groups, with the Southern Baptists the emergence of anti–Vietnam War protest, and with the Episcopalians the permitting of women priests.