For centuries following the fall of Rome, western Europe was a benighted backwater, a world of subsistence farming, minimal literacy, and violent conflict. Meanwhile Arab culture was thriving, dazzling those Europeans fortunate enough to catch even a glimpse of the scientific advances coming from Baghdad, Antioch, or the cities of Persia, Central Asia, and Muslim Spain. T here, philosophers, mathematicians, and astronomers were steadily advancing the frontiers of knowledge and revitalizing the works of Plato and Aristotle. I n the royal library of Baghdad, known as the House of Wisdom, an army of scholars worked at the behest of the Abbasid caliphs. At a time when the best book collections in Europe held several dozen volumes, the House of Wisdom boasted as many as four hundred thousand. Even while their countrymen waged bloody Crusades against Muslims, a handful of intrepid Christian scholars, thirsty for knowledge, traveled to Arab lands and returned with priceless jewels of science, medicine, and philosophy that laid the foundation for the Renaissance. I n this brilliant, evocative book, Lyons shows just how much "Western" culture owes to the glories of medieval Arab civilization, and reveals the untold story of how Europe drank from the well of Muslim learning.