Concentrating on ideology and cultural values, Liberty, Virtue, and Progress explores the motivations that casued Northerners to fight America's Civil War. Arguing for the primary significance of ideals and cultural values in defining a war, the book examines the opinions of both the Northern soldier and civilian about the meaning of the Civil War in terms of defining American nationalism, the character of the American people, and the future of free government. The book addresses the intellectual and social elites of Northern society, but gives a new emphasis to the opinions of the common man on the subject and ideology of the war.

In addition to identifying and discussing the ideas and cultural values that played a role in motivation, Hess looks at how the experience of war (battlefield death and suffering) interacted with that ideology. Contrary to the commonly held belief that war is disruptive to pre-war ideals, Hess argues that Northern soldiers and civilians made a conscious effort to use ideology as a tool with which to retain their faith in ideas. Liberty, Virtue, and Progress is based on extensive research in both published and unpublished sources.