Textbook author. Born in Bonnybridge (Falkirk), the son of a railway official, Duncan was educated in Larbert, Grangemouth and Perth. His university education, at St. Andrews, was interrupted by wartime service in the Royal Corps of Signals. Thereafter he taught physics in various English schools before joining Liverpool University as an education lecturer in 1958. He wrote a succession of school textbooks, including Electronics and Nuclear Physics (1966), the Exploring Physics series, which made his reputation, and GCSE Physics (1987, with several subsequent editions). His books sold millions of copies and were translated into many languages.