Modern scholarship has exposed the intrinsic importance of medieval science and confirmed its role in preserving and transmitting Greek and Arabic achievements. This Source Book offers a rare opportunity to explore more than ten centuries of European scientific thought. In it are approximately 190 selections by about 85 authors, most of them from the Latin West. Nearly half of the selections appear here for the first time in any vernacular translation.The readings, a number of them complete treatises, have been chosen to represent “science” in a medieval rather than a modern sense. Thus, insofar as they are relevant to medieval science, selections have been drawn from works on alchemy, astrology, logic, and theology. Most of the book, however, reflects medieval understanding of, and achievements in, the mathematical, physical, and biological sciences. Critical commentary and annotation accompany the selections. An appendix contains brief biographies of all authors.This book will be an indispensable resource for students and scholars in the history of science.