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.