John Mullan's celebrated construction project-a 625-mile link that connected the Missouri and Columbia rivers-established the West Point graduate as an accomplished road builder. After completing the West's first engineered highway at age thirty-two, he lived for nearly another half century, a period of dynamic change. When he died in 1909, automobiles were making their initial crossings along the route he engineered, and his arterial eventually became a critical link in America's longest interstate freeway, I-90. Yet despite frequent mentions in books about the nineteenth century Northwest, the soldier/explorer has remained little more than a caricature: a dashing young Army officer who comes West, builds one of its most important thoroughfares, and then disappears from the region's literature. Now, in lively prose, Idaho State Historian Keith Petersen takes a fresh look at Mullan's road, which has significantly impacted the development of the Northwest for more than 150 years. The deeply researched biography also probes Mullan's complex personality and continues the story, including business partnerships and personal relationships with some of the West's most intriguing characters: Father Pierre-Jean DeSmet, General William T. Sherman, Chico founder John Bidwell, Idaho gold discoverer Elias Pierce, Yakama Indian chief Owhi, and others. Long overdue, Petersen's comprehensive portrayal bestows a full appreciation of Mullan's life-his rise to fame as well as his fall from grace.