For centuries following the fall of Rome, Western Europe was backward and benighted, locked into the Dark Ages and barely able to tell the time of day. Arab culture, however, was thriving, and had become a powerhouse of intellectual exploration and discussion that dazzled the likes of British adventurer Adelard of Bath. The Arabs could measure the earth's circumference (a feat not matched in the West for eight hundred years); they discovered algebra; were adept at astronomy and navigation, developed the astrolabe, translated all the Greek scientific and philosophical texts including, importantly, those of Aristotle. Without them, and the knowledge that travelers like Adelard brought back to the West, Europe would have been a very different place over the last millennium. Jonathan Lyons restores credit to the Arab thinkers of the past in this riveting history of science - from its earliest and most thrilling days.