'Keys to Science', al-Khwarizmi's classic on physical sciences. Official 2020 reprint of Brill 1895 edition. In this book Khwarizmi provides answers to many unresolved questions among the Arabs. Abu Abd Allah Muhammad ibn Musa al-Khwarizmi, the famous mathematician, astronomer and geographer, contributed greatly to the advancement of the Mathematical sciences, and his work 'Muqtasar fi al-Jabr' led to the use of 'Algebra' and 'Zero'.