Tracing over a century of transformation in the relationship between humans and our "best friend," from hunting companion to laboratory commodity to modern pet. Intrepid, docile, and cloaked in coats of white, black, and tan, beagles were one of the most popular breeds in the United States in the twentieth century. From Snoopy to dog shows, many Americans loved and identified with beagles. But during the same period, as scientists searched for a standard research dog, beagles emerged as something else: an ideal animal for laboratory experimentation. In Lab Dog, historian Brad Bolman explains how the laboratory dog became a subject of intense focus for twentieth-century scientists and charts the beagle's surprising trajectory through global science. Following beagles as they moved from eugenics to radiobiology, pharmaceutical testing to Alzheimer's studies, Lab Dog sheds new light on pivotal stories of twentieth-century science, including the Manhattan Project, tobacco controversies, contraceptive testing, and behavioral genetics research. Bolman shows how these experiments shaped our understanding of dogs as intelligent companions who deserve moral protection and socialization--and in some cases, daily medication. Compelling and accessible, Lab Dog tells the thorny story of the participation of beagles in science, including both their sacrifices and their contributions, and offers a glimpse into the future of animal experimentation.