James Clerk Maxwell is one of history's most influential scientists — in Einstein's words, the man with whom "one scientific epoch ended and another began" — yet he remains far less known to the public than contemporaries like Faraday, Newton, or Einstein himself. In this biography, engineer-turned-writer Basil Mahon traces Maxwell's life from his boyhood on a Scottish country estate through Edinburgh, Cambridge, and professorships at Aberdeen, London, and Cambridge's Cavendish Laboratory. Along the way, Maxwell unified electricity, magnetism, and light into a single theory of electromagnetism, took the world's first colour photograph, explained the true nature of Saturn's rings, and helped found the kinetic theory of gases — reshaping physics before his death at just 48. Drawing on Maxwell's letters and the accounts of those who knew him, Mahon paints a warm, human portrait of a brilliant and much-loved man, and makes his ideas accessible to readers with no scientific background.