In the middle of a frigid Sunday night in January 1856, a twenty-two-year-old Kentucky slave named Margaret Garner gathered up her family and raced north, toward Cincinnati and freedom. But Margaret's master followed just hours behind and soon had the fugitives' sanctuary surrounded. Thinking all was lost, Margaret seized a butcher knife and nearly decapitated her two-year-old daughter, crying out that she would rather see her children dead than returned to slavery.

She was turning on her other three children when slave-catchers burst in and subdued her.

Margaret Garner's child-murder electrified the United States, inspiring the longest, most spectacular fugitive-slave trial in history. Abolitionists and slaveholders fought over the meaning of the murder, and the case came to symbolize the ills of the Union in those last dark decades before the Civil War. Newspaper columnists, poets, and dramatists raced to interpret Margaret's deeds, but by century's end they were all but forgotten.

Steven Weisenburger is the first scholar to delve into this astonishing story in more than a century.