For many years, ornithology was the province of the wealthy gentleman hunter who shot, stuffed, and preserved his specimens, and of the museum that collected simply to document natural history, not to analyze it. Even as evolutionary theory began to make its mark on the study of birds, it remained a science heavily populated by amateurs. Daniel Lewis here explores the professionalization of ornithology through one of its key figures: Robert Ridgway, the Smithsonian Institution's first curator of birds and one of North America's most important natural scientists. Exploring a world in which the divisions of status, rigour, and publication between amateurs and professionals were far more blurred than the worlds that appear in most histories of science, Daniel Lewis offers a vivid introduction to Ridgway and shows how his work had a larger international context that influenced the evolution of American ornithology.