Alfred North Whitehead (1861-1947) has made an enormous impact upon philosophical thinking. His work continues to fascinate, and occasionally to exasperate, Whitehead’s ‘Principia Mathematica’ (jointly offered with Russell) is crucial to an understanding of recent philosophy of logic and of mathematics. Whitehead’s metaphysics has proved formidably difficult yet stimulating. With his ideas on God he fathered a major school of modern theology.