Lost Enlightenment recounts how, between the years 800 and 1200, Central Asia led the world in trade and economic development, the size and sophistication of its cities, the refinement of its arts, and, above all, in the advancement of knowledge in many fields. Central Asians achieved signal breakthroughs in astronomy, mathematics, geology, medicine, chemistry, music, social science, philosophy, and theology, among other subjects. They gave algebra its name, calculated the earth's diameter with unprecedented precision, wrote the books that later defined European medicine, and penned some of the world's greatest poetry. One scholar, working in Afghanistan, even predicted the existence of North and South America--five centuries before Columbus. Rarely in history has a more impressive group of polymaths appeared at one place and time. No wonder that their writings influenced European culture from the time of St. Thomas Aquinas down to the scientific revolution, and had a similarly deep impact in India and much of Asia.