This book explores the life and legacy of Alexander Wetmore, a leading American ornithologist and sixth Secretary of the Smithsonian Institution, as a lens to examine the role of science in U.S.–Latin American relations during the twentieth century. Through nearly forty expeditions across Latin America, Wetmore forged lasting ties with local scientists, institutions, and communities, contributing significantly to ornithological knowledge and Pan-American scientific exchange. Drawing on an extensive archive of personal and professional documents, the book offers a richly detailed account of Wetmore's career and his engagement with the region, revealing how science, diplomacy, and power intersected in shaping hemispheric relations. Moreover, Wetmore's archive contains a large and varied collection of photographs. A selection of these images, bringing to life his work and his vision of the region, is included in the book.