Between 1900 and 1950, Americans built the most powerful steam locomotives of all time - enormous engines that powered a industry of colossal scale and intensity. They were deceptively simple machines yet even as the technology was being perfected it was becoming obscure. Despite immense and sustained effort, they remained grossly inefficient in their use of increasingly costly fuel and labor. In the end, they baffled their masters and, as soon as diesel-electric technology provided an alternative, the steam locomotive disappeared from American railroads. Drawing on the work of eminent engineers and railroad managers of the day, this lavishly illustrated history chronicles the challenges, triumphs and failures of steam locomotive development and operation.