This study of Dubuque, Iowa, during the 1860s argues that military service in the Civil War made a significant contribution to the creation of an American working class, a contribution which has been largely ignored by historians. The analysis is pursued through ten chapters. The first two chapters describe the city of Dubuque on the eve of the war. Dubuque emerged as a regional commercial center during the 1850s, but rapid growth and the Panic of 1857 created a sense of social crisis focused especially on young men and the adult working class. The third and fourth chapters continue the Dubuque story into the 1860s, examining economic and social developments during the 1860s, the city's responses to the war, and the process of raising soldiers for the Union Army. The fifth chapter presents a quantitative analysis of Dubuque's soldiers, arguing that, contrary to recent analyses by Maris A. Vinovskis and others, for Dubuquers the Civil War was indeed a "poor man's fight." Chapters six through eight analyze the experiences of Dubuque's soldiers in the army, using their military service records, letters, diaries, and court martial and pension records. Taken together, these three chapters argue that life and work in the Union Army prepared men for a post-war industrial-capitalist society. In his penetrating analysis of the "face of battle," John Keegan argues that twentieth-century industry offered men "pre-conditioning for battle." These three chapters argue the converse of Keegan's argument: Nineteenth-century military service helped "pre-condition" men for urban-industrial lifestyles. The final chapters return to the city of Dubuque. Chapter nine considers what happened to the soldiers' families during the war; while the soldiers were being conditioned in the military for urban-industrial life, so were their families at home. And chapter ten traces Dubuque's veterans and non-veterans into civilian life through the 1870 Census, concluding that, although less socially mobile, the veterans were more stable geographically. Veterans, in other words, formed an important nucleus for the working class in Dubuque.