A.N. Whiteheadred North Whitehead (1861–1947) began his career writing primarily on mathematics and logic. His book Principia Mathematica (with Bertrand Russel) is widely considered one of the most important texts in mathematical logic of the twentieth entury. Later turning to the philosophy of science and metaphysics, he pioneered process philosophy, which looks at reality as a constantly evolving, interconnected web of events and processes rather than a collection of fixed substances. Adventures of Ideas and Science and the Modern World reflect on the power of general ideas – about humanity, God, and the universe – to shape the course of civilization, the latter book focusing particularly on the influence of science.