This collection investigates the evolution of American intellectual life during the transformative period between the Civil War and the First World War. Perry Miller, a distinguished historian of American thought, curates a selection of primary source documents to illustrate how the nation grappled with industrialization, the rise of pragmatism, and the shifting definitions of democracy. By framing these texts within his own scholarly introduction, Miller provides a framework for understanding the transition from traditional religious and moral frameworks to the modern secular and scientific outlooks that defined the early twentieth century.

Scholars frequently cite this volume as a foundational resource for understanding the intellectual climate of the Gilded Age and the Progressive Era. Readers often note the academic density of the prose, which assumes a baseline familiarity with American history and philosophical concepts.