He has written and broadcast extensively on imagery in art and science from the Renaissance to the present day. He speaks on issues of visualisation and lateral thinking to a wide range of audiences. Leonardo da Vinci has been the subject of books written by him, including Leonardo (Oxford University Press 2004). He has published on imagery in the sciences of anatomy, natural history and optics, including The Science of Art: Optical Themes in Western Art from Brunelleschi to Seurat (Yale University Press).

He was trained in Natural Sciences and Art History at Cambridge University and the Courtauld Institute of Art, University of London. He wasBritish Academy Wolfson Research Professor (1993-98). For more than 25 years he was based in Scotland (University of Glasgow and University of St Andrews). He has held visiting posts in Princeton, New York, North Carolina, Los Angeles and Montreal.

He has curated a series of exhibitions on Leonardo and other themes, including Spectacular Bodies at the Hayward Gallery in London,Leonardo da Vinci: Experience, Experiment, Design at the Victoria and Albert Museum in 2006 and Seduced: Sex and Art from Antiquity to Now, Barbican Art Gallery, London, 2007. He was also guest curator for Circa 1492 at the National Gallery of Art in Washington in 1992.