This book investigates a crucial -- but forgotten -- episode in the history of medicine. In it, Thomas Schlich systematically documents and analyzes the earliest clinical and experimental organ transplant surgeries. In so doing he lays open the historical origins of modern transplantation, offering a new and original analysis of its conceptual basis within a broader historical context. This first comprehensive account of the birth of modern transplant medicine examines how doctors and scientists between 1880 and 1930 developed the technology and rationale for performing surgical organ replacement within the epistemological and social context of experimental university medicine. The clinical application of organ replacement, however, met with formidable obstacles even as the procedure became more widely recognized. Schlich highlights various attempts to overcome these obstacles, including immunological explanations and new technologies of immune suppression, and documents the changes in surgical technique and research standards that led to the temporary abandonment of organ transplantation by the 1930s. Thomas Schlich is Professor and Canada Research Chair in the History of Medicine at McGill University.