In his time Isambard Kingdom Brunel was the world's greatest engineer. His list of achievements is truly breathtaking: the Thames Tunnel, the first underwater tunnel in the world; the SS Great Britain, the first propeller-driven ship; the Clifton Suspension Bridge, then the longest span of any bridge in the world; and the Great Western Railway. History has been kind to his memory: many of his creations still exist and he is lauded by historians as a truly 'Great Briton'. In this full-scale biography Colin Maggs presents a portrait of a complex, ambitious and determined genius. But the Brunel that emerges is not without flaws. He made mistakes, both personal and technical – he wasn't always right but never admitted he was wrong. Drawing on Brunel's diaries, letters and business papers, we see the real Isambard, a more human figure, emerging from behind the towering structures and machines he created.