Ardley joined the editorial staff of the World Book Encyclopedia in 1962, when the London branch of the American publisher was producing an international edition. This took four years, during which time he developed the skill of editing and writing introductory material for the young. After a brief period working for Hamlyn, he became a freelance editor in 1968 (which enabled him to continue with his musical career), and then in the 1970s moved into writing introductory books, mostly for children, on natural history (especially birds), science and technology, and music, such as What Is It?. Just as his composing and performance had been moved forward by the introduction and development of technology, so too with his publishing career as computers began to become more and more important. In 1984 Ardley began to write mainly for Dorling Kindersley, producing a series of books which included the best-selling (over three million copies worldwide) and award-winning The Way Things Work, illustrated by David Macaulay. When he retired in 2000 Ardley had written 101 books, with total sales of about ten million.