This article is from the U.S. Civil War FAQ, by Justin M. Sanders email@example.com with numerous contributions by others.
David M. Potter, The Impending Crisis, 1848-1861 (Harpers & Row, 1976).
This book covers, primarily from a political perspective, the events
leading to the war from the Mexican Cession in 1848 through Fort Sumter.
Judged by the weight of footnotes, this is a very serious historical work,
but Potter reaches beyond mere facts and manages to relate a sense of the
personalities and motives behind the events. A very enjoyable read. In
the preface of "Battle Cry of Freedom," McPherson lists this book as one
of the handful of classics on the Civil War period. 638 p.
Bruce and William Catton, Two Roads To Sumter. 1963.
Compares the lives of Lincoln and Davis starting with their births
close together in time and space. It then uses their two diverging lives
as a microcosm of the national drift to war.
Richard N. Current, Lincoln and the First Shot. 1963.
A vivid narrative and scholarly analysis of the decision to resupply,
and not to surrender, Fort Sumter. Regards Lincoln's second inaugural as
containing a succinct and true characterization of the crisis - that both
sides preferred war to compromise - and that Lincoln felt that to
compromise on Fort Sumter without the Southern states promising to
dissolve their secession conventions was futile appeasement.
William Freehling, Road to Disunion: The Secessionists at Bay 1787-1854.
A good, though idiosyncratic, one volume treatment of the South's
development of the secessionist mindset.
Phillip Shaw Paludan, A People's Contest: The Union and Civil War.
David M. Potter, Lincoln and His Party in the Secession Crisis. 1942.
A professional historian's treatise. Not light reading, but a quite
compelling account of the blunders and circumstances that led to the
outbreak of war.