Ecological Imperialism: The Biological Expansion of Europe, 900-1900 is a 1986 book by environmental historian Alfred W. Crosby. The book builds on Crosby's earlier study, The Columbian Exchange, in which he described the complex global transfer of organisms that accompanied European colonial endeavors. Ecological Imperialism is considered a foundational text in the field of environmental history and has been influential in many other fields, including postcolonial studies. It was awarded the 1987 Ralph Waldo Emerson Award.