A vibrant portrait of an age when Arabic enlightenment anticipated and inspired the European Renaissance, illuminated by its guiding figures and rivals, Ibn Sina and Biruni. In The Genius of their Age, S. Frederick Starr follows up his acclaimed Lost Enlightenment: Central Asia's Golden Age with a portrait of the Arab enlightenment and its key figures--Abu-Ali al-Husayn ibn-'Abdallah Ibn-Sina and Abu al-Rayhan Muhammad ibn Ahmad al-Biruni. A thousand years ago, these two intellectual giants--known as Ibn Sina and Biruni for short--achieved stunning breakthroughs in fields as diverse as medicine, astronomy, mathematics, philosophy, geography, and physics. Biruni measured the earth more precisely than anyone else down to the sixteenth century, pondered a heliocentric universe, and hypothesized the existence of North and South America as inhabited continents. Ibn Sina's writing on philosophy and metaphysics enriched the writings of countless European thinkers, including St. Thomas Aquinas, while Sina's grand synthesis of medical knowledge became the standard for the next six hundred years in Europe, the Middle East, and India. They both also commented extensively on the works of ancient Greeks and earlier Muslim thinkers, whose works they aspired to synthesize--and to transcend. Contemporaries, Ibn Sina and Biruni were born within the borders of what is now Uzbekistan and spent their lives in Central Asia. They also became rivals, launching a correspondence and commentary that galvanized them despite sometimes bitter disagreement. Centuries before the West caught up with them, Ibn Sina and Biruni reflected their age's feats and its intellectual high point, persisting with their inquiries and their independence amid turmoil and rapid change. Though scholars have long dissected the works of Ibn Sina and Biruni, S. Frederick Starr focuses also on their lives and the times in which they lived. By contextualizing their work and by making the age palpable to the reader, S. Frederick Starr gives the achievements of Ibn Sina and Biruni a holistic and unforgettably human dimension.