The Reformation of American Quakerism, 1748-1783 offers a detailed history of the withdrawal of the Society of Friends from mainstream America in the years between 1748 and the end of the American Revolution. Jack D. Marietta examines the causes, course, and consequences, both social and political, of the Quakers' retreat from prominent positions in civil government while at the same time developing a more distinctive and "purified" religious community. These changes amounted to a watershed in the greater history of the Society of Friends, a turning away from its engagement with the world on behalf of a Whig political philosophy and toward a role as critic and gadfly on the periphery of political society.

Less conspicuously but perhaps more dramatically, the internal transformation of the Society through the strengthening of the members' commitment to a host of Quaker sectarian values—among them exogamy, "guarded" childrearing, sexual continence, honesty, simplicity, humility, and asceticism—was enforced by the reformers' stern determination that members would either conform to these mores or face expulsion from the Society. These changes resulted in the revitalization of the society and made possible the Quakers' campaign against slavery, thus distinguishing them as the first group of people in history to espouse abolition.

Marietta draws on a wealth of data: over 10,000 disciplinary cases in the Society's records dating from 1682. The author's description and evaluation of the role, status, and treatment of women in the Society is sympathetic, and what emerges from his interpretation is a sensitive portrayal not only of withdrawal but of the substitution of a vision different from the one that inspired the Holy Experiment.