Book excerpt: Adelard of Bath was one of the most colourful personalities of the Middle Ages. He travelled to the Crusader kingdoms, to Sicily and south Italy, and translated texts on astronomy, astrology and magic from Arabic into Latin. He acquired a lasting reputation as a pioneering mathematician, and he was a gifted teacher. He addressed one of these works, on cosmology and the astrolabe, to the future King Henry II, and it is in the context of the education of the nobility that the three works edited in this book are to be viewed. Adelard meant them to be both entertaining and instructive. They deal with all kinds of topics, from the nature of the soul to the cause of earthquakes, from the effects of music to how to train a hawk. A preface provides the results of research on Adelard's life and work.