This work investigates the profound and multifaceted impact of evolutionary theory on American intellectual, social, and political life from the mid-nineteenth century through the mid-twentieth century. Stow Persons, a distinguished historian of American thought, examines how the concept of evolution transcended biology to reshape American perspectives on progress, democracy, and the nature of society. By synthesizing a wide array of primary sources, the author maps the transition from early religious and static worldviews to a dynamic, evolutionary understanding of human development.

This text is regarded as a foundational study in the field of American intellectual history, noted for its rigorous documentation and clear thematic organization. The work provides a dense, scholarly examination of how scientific concepts permeate and transform a nation's broader cultural consciousness.