Alfred North Whitehead was born in Ramsgate, England, in 1861, and spent the first half of his career as a mathematician, first at Cambridge and then at University College London and Imperial College. His central early achievement, written jointly with his former student Bertrand Russell over the following decade, was Principia Mathematica, published in three volumes between 1910 and 1913, an attempt to derive the whole of mathematics from a small set of logical axioms that remains one of the most ambitious works in the foundations of mathematics, whatever the later technical objections raised against its completeness.
In 1924, already in his sixties, Whitehead accepted a professorship of philosophy at Harvard, a late career shift that would have ended most academics' major output; instead it opened his most original and lasting period of work. His Gifford Lectures at the University of Edinburgh in 1927 and 1928 became Process and Reality, published in 1929, and the philosophy it set out, that reality is constituted not by fixed enduring substances but by momentary events of experience, actual occasions, each arising, becoming and perishing in a continuous creative process, occupied him until his death in 1947 and gave his name to an entire school of subsequent philosophy and theology.