Through an examination of religious life in a typical northern rural locale—Cortland County, New York—from 1790 to 1860, Curtis D. Johnson adds to our understanding of the Second Great Awakening, an intellectual and religious watershed in American history. Offering both quantitative and qualitative analyses of churches' memberships, ideologies, and activities, he maintains that scholars have misunderstood the historical significance of evangelicalism.

Johnson contends that these churches did not constitute society, nor were they microcosms of it; rather, they evolved from embattled congregations of the saved—"islands of holiness"—to ideologically conservative, organizationally unified, integrated parts of society. He uncovers the many diversities of Protestantism in the form of splits between evangelicals and non-evangelicals, formalists and anti-formalists, Arminians and Calvinists, Old School traditionalists and Oberlin perfectionists, church members and religious society members.

At the heart of the revivalistic impulse, he argues, was ideological conflict—primarily between Calvinists and Arminians—with gender politics and internal church dynamics also contributing to the evangelical tumult. With a special interest in the Awakening's impact on congregational life, Johnson focuses on rural community experience to challenge the findings of historians who have concentrated exclusively on urban religious expression. He concludes that the importance of the various factions of evangelicalism lies in their common exhortation to republicanism and reform: these congregations, he says, influenced social change out of proportion to their numbers because activism was a central tenet of their religion.

Islands of Holiness is a gem of local history. A meticulously researched book, it makes a valuable contribution to an enduring aspect of the social history of American religious expression.