James McDonald is a British polymath: mathematician, etymologist, historian, theologian and non-fiction writer. He writes on a range of topics including Gnostic Dualism, the Cathars of the Languedoc and their theology, the Counts of Toulouse, Occitania, Medieval warfare and the Medieval Inquisition. His work is characterised by combining serious scholarship with an entertaining style. Something of a polymath, he has also written on subjects as diverse as computer simulation, mathematical problems, philosophy, etymology and comparative philology. For several years he wrote a weekly column on English word origins for the Sunday Express, a national newspaper in the UK.