Alan Alexander (A.A.) Milne was born in London in 1882. He was educated at Westminster School and Trinity College, Cambridge where he studied mathematics. Whilst at university he edited the undergraduate magazine Granta and, after graduation in 1903, pursued a career writing articles for newspapers and magazines, including Punch and St. James' Gazette. In 1906 he joined the staff of Punch, becoming the magazine's assistant editor.
In 1913, Milne married Dorothy Daphne de Selincourt "She laughed at my jokes," he wrote later in his autobiography.
Despite being a pacifist, Milne volunteered to fight in the First World War with the Royal Warwickshire Regiment as a signals officer and ended up on the Somme in 1916. He also wrote propaganda for the Intelligence service. The horrors of the war left him with a lifelong idealised nostalgia for childhood. "A 'children's book' must be written, not for children, but for the author himself," he once said. When the disillusioned post-war writers depicted the "lost generation" of the 1920s, Milne returned in his Pooh books into the safety of his early years.
After the war Milne's success continued with a series of plays and novels produced in both London and Broadway and their popularity enabled him to buy, in 1925 a country home, Cotchford Farm, on Ashdown Forest. The family used the Farm as a week-end retreat, spending most of their time in London. Most of the time the family still spent in London, going down to Cotchford only at week-ends.
Milne continued writing and publishing throughout the 1930s and 40s. At the age of fifty-six (1938) he published his autobiography which focused mostly on his childhood years. An operation on Milne's brain in 1952 left him an invalid during the last four years of his life. He died in Hartfield, East Sussex, on January 31, 1956. After his wife's death in 1971, part of the fortune earned by the Pooh books came to the Royal Literary Fund, providing for writers in financial distress.