Abu Hanifah Nu'man ibn Thabit (d. 150/767) is one of the great pioneers in the history of Islamic law. He was among the first to deploy the recognized methods of legal reasoning consistently, and to gather the judgments and rulings of his time into a systematic corpus. The fiqh that evolved from his style of reasoning, carried on by his brilliant students, become associated with his name. The Hanafi School is the one most widely followed among the world's Sunni Muslims. This study of Abu Hanifah's life and legacy is based on the traditional sources. It includes a short survey of how Hanafi fiqh evolved in different regions of the Islamic world. It offers a clear reminder of the criteria and conditions traditionally applied before any ruling gained general acceptance.