Duncan grew up in London and read English at Jesus College, Cambridge. He is the editor of Ronald Skirth's First World War memoir The Reluctant Tommy (Macmillan, 2010) and co-author of Star Trek: The Human Frontier (Polity, 2000) and Zippy and Me: The Remarkable Life in Puppets of Rainbow's Ronnie Le Drew (forthcoming, 2011). He also works as an actor and occasional theatre director.