Eric Foner, the preeminent historian of the Civil War era, provides the foundational study of the ideology that animated the Republican Party from its founding in the 1850s through its triumph in the election of 1860. Foner argues that Republicans were united not simply by opposition to slavery's expansion but by a coherent vision of free labor society that contrasted sharply with the slave South. This ideology held that in a proper society, labor was dignified, workers could rise through effort, and economic independence was achievable by all white men. Foner traces how this vision drew on Northern economic development, Protestant moral reform, and emerging ideas about self-made manhood, while also containing tensions over race, immigration, and the proper role of government. The book examines the diverse strands within Republican thought--former Whigs, former Democrats, abolitionists, nativists, pragmatists, and radicals--showing how they held together despite significant differences. Foner's analysis of Republican ideology proves essential for understanding not just why the Civil War came but what the North was fighting for and how Reconstruction's possibilities and limitations were shaped by antebellum ideas. First published in 1970 and never superseded, this book remains required reading for anyone seeking to understand the political origins of America's greatest crisis.