Thomas L. Kane (1822--1883), a crusader for antislavery, women's rights, and the downtrodden, rose to prominence in his day as the most ardent and persuasive defender of Mormons' religious liberty. Though not a Mormon, Kane sought to defend the much-reviled group from the "Holy War" waged against them by evangelical America. His courageous personal intervention averted a potentially catastrophic bloody conflict between federal troops and Mormon settlers in the now nearly forgotten Utah War of 1857--58. Drawing on extensive, newly available archives, this book is the first to tell the full story of Kane's extraordinary life. The book illuminates his powerful Philadelphia family, his personal life and eccentricities, his reform achievements, his place in Mormon history, and his career as a Civil War general. Further, the book revises previous understandings of nineteenth-century reform, showing how Kane and likeminded others fused Democratic Party ideology, anti-evangelicalism, and romanticism.