The Muslim Empire -- An extraordinary story -- Muhammad, Prophet of Islam -- Islam and the Muslims -- A century of conquest -- An immense empire -- In the city or in the country? -- Everyday life in the city -- The paths of knowledge -- Adventures in learning -- 9th century Baghdad -- Al-khwarizmi introduces the number zero -- 10th century Cairo -- Alhazen : master of light -- 11th century Esfahan -- Avicenna completes his book of medicine -- 12th century Palermo -- Al-Idrisi maps the known world -- 14th century Damascus -- Ibn al-Shatir measures time.