This work investigates the historical impact of human expansion on the biodiversity of North America, specifically documenting the decline and extinction of native species. Peter Matthiessen, a naturalist and writer, synthesizes historical records, colonial accounts, and biological data to construct a comprehensive narrative regarding the anthropogenic causes of species loss. The text argues that the systematic exploitation of natural resources has fundamentally altered the continent's ecological integrity.

Experts and conservationists frequently cite this volume as a foundational text for understanding the history of American environmental policy. Readers often note the dense, descriptive prose that balances scientific observation with a somber historical narrative.