Three historians examine what drove southern secession in the winter of 1860-1861 and why it culminated in the American Civil War. Politicians and opinion leaders on both sides of the Mason-Dixon line struggled to formulate coherent responses to the secession of the deep South states. The Confederate attack on Fort Sumter in mid-April 1861 triggered civil war and the loss of four upper South states from the Union. The essays by three senior historians in Secession Winter explore the robust debates that preceded these events. For five months in the winter of 1860–1861, Americans did not know for certain that civil war was upon them. Some hoped for a compromise; others wanted a fight. Many struggled to understand what was happening to their country. Robert J. Cook, William L. Barney, and Elizabeth R. Varon take approaches to this period that combine political, economic, and social-cultural lines of analysis. Rather than focus on whether civil war was inevitable, they look at the political process of secession and find multiple internal divisions—political parties, whites and nonwhites, elites and masses, men and women. Even individual northerners and southerners suffered inner conflicts. The authors include the voices of Unionists and Whig party moderates who had much to lose and upcountry folk who owned no slaves and did not particularly like those who did. Barney contends that white southerners were driven to secede by anxiety and guilt over slavery. Varon takes a new look at Robert E. Lee’s decision to join the Confederacy. Cook argues that both northern and southern politicians claimed the rightness of their cause by constructing selective narratives of historical grievances.