This book was not commissioned, nor was the author assigned the task of writing a history of the School of Medicine of the University of Pennsylvania. The idea to write this history arose after I read the critique of a grant request to the National Institutes of Health, which gave my proposal an unfundable priority score. The reviewers' criticisms of the proposed experiments were so contrary to concepts that I thought lead to great discoveries that I wondered what factors are involved in making scientific advances. Realizing that a number of important advances in medical science had been made from time to time by my colleagues at the University of Pennsylvania School of Medicine, I decided to examine systematically how these scientists' ideas originated and their advances were made. What I thought would be a relatively easy task soon became a complex one, for I soon found that, in addition to the many scientific contributions made by the faculty, the School of Medicine had a history that was richer and more distinguished than I or anyone I talked with realized. To my surprise, my investigations uncovered the fact that, even before the end of the eighteenth century, the faculty of the Medical "Department" had begun original experimentation and, within a short time, had made discoveries equaling those of their colleagues in Europe. As the new country developed, the Medical Department made every effort within its often meager means to improve its teaching, rebuild its facilities, and meet the medical challenges of a growing nation.