The origins of the astrolabe are unknown but during the Middle Ages and Renaissance it was the pre-eminent astronomical and astrological instrument. The author describes Renaissance astrolabes and their origins in this detailed study. 'The dozen essays in this remarkably unified ensemble have been gathered together from seven different books or journals... Turner [...] has produced a tour de force of perceptive erudition. 'Material culture' now rises to a truly professional and sophisticated level.' Annals of Science