Despite the intensive research of the past quarter century, there still is no single book that examines all major aspects of the medieval scientific enterprise in depth. This illustrated volume is meant to fill that gap. In it sixteen leading scholars address themselves to topics central to their research, providing as full an account of medieval science as current knowledge permits. Although the book is definitive, it is also introductory, for the authors have directed their chapters to a beginning audience of diverse readers, including undergraduates, scholars specializing in other fields, and the interested lay reader. The book is not encylopedic, for it does not attempt to provide all relevant factual data; rather, it attempts to interpret major developments in each of the disciplines that made up the medieval scientific world. Data are not absent, but their function is to support and illustrate generalizations about the changing shape of medieval science. The editor, David C. Lindberg, has written a Preface in which he discusses the growth of scholarship in this field in the twentieth century.