Ian Stewart was born in 1945, educated at Cambridge (MA) and Warwick (PhD). He also has four honorary doctorates from Westminster, Louvain, Kingston, and the Open University. He is Professor of Mathematics at Warwick University and Director of the Mathematics Awareness Centre. He has held visiting positions in Germany, New Zealand, and the USA, and is an adjunct professor at Houston.

He is an active popularizer of mathematics and related areas of science. In 1995 he was awarded the Royal Society's Michael Faraday Medal for furthering the public understanding of science. His book Nature's Numbers was shortlisted for the 1996 Rhone-Poulenc Prize for Science Books. He delivered the 1997 Royal Institution Christmas Lectures on BBC television and repeated them for NHK in Japan in 1998. He is winner of the 1999 Communications Award of the Joint Policy Board for Mathematics, and he was awarded the 2000 Gold Medal of the UK's Institute for Mathematics and Its Applications. His joint book The Science of Discworld was nominated for a Hugo award at the 2000 World science fiction convention. Jointly with M. Golubitsky he won the 2001 Balaguer Prize. He was elected a Fellow of the Royal Society in 2001, and won the Public Understanding of Science and Technology Award of the American Association for the Advancement of Science in 2002.

He contributes to a wide range of newspapers and magazines in the UK, Europe, and the USA, including New Scientist and Scientific American. He is the mathematics consultant for New Scientist, and has been a consultant for Encyclopaedia Britannica.