How did use of medical technology such as urinalyses, blood tests, and x-ray machines change patient care in early-twentieth-century American hospitals? To what extent was the use of new machines influenced by the ideas of scientific medicine and to what extent by the availability of newly structured facilities and trained personnel? Drawing on the medical treatment of more than 2,000 patients in Pennsylvania and New York hospitals, Howell traces the ways in which medical technology was used, not merely how it was talked about. He utilizes a wide range of sources—including medical texts, popular literature, and the visual arts—to explore how technology came to be such a central feature of medical care. Howell also shows how changes in medical practice raised issues of gender, culture, and economics. Howell's analysis is especially timely in light of the ongoing debate over U.S. health care reform, a debate in which a central topic is the use and expense of medical technology. In a concluding chapter he applies the book's historical insights to medical practice today—asking why, for example, modern diagnostic tests have not been used to give doctors more time to spend with patients.