God's Clockmaker is a biography of England's greatest medieval scientist, a man who solved major practical and theoretical problems to build an extraordinary and pioneering astronomical and astrological clock. Richard of Wallingford (1292-1336), the son of a blacksmith, was a brilliant mathematician with a genius for the practical solution of technical problems. Trained at Oxford, he became a monk and then abbot of the great abbey of St. Albans, where he designed his clock. His achievement is a striking example of the sophistication of medieval science, based on knowledge handed down from the Greeks and the Arabs.