Walter Stahr, a lawyer turned biographer who previously wrote lives of William Seward and John Jay, provides the first full-scale biography of Salmon P. Chase, one of the nineteenth century's most important antislavery politicians. Chase served as a United States Senator, Governor of Ohio, Lincoln's Treasury Secretary, and Chief Justice of the United States, playing a crucial role at every stage of slavery's destruction and Reconstruction's implementation. Stahr traces Chase's early career as a lawyer who defended fugitive slaves and helped establish the legal arguments against slavery's expansion, earning him the nickname 'Attorney General for Fugitive Slaves.' As Treasury Secretary during the Civil War, Chase innovated the financing that kept the Union army in the field while simultaneously pressing Lincoln toward emancipation. As Chief Justice, he navigated the treacherous politics of Reconstruction, presiding over Andrew Johnson's impeachment trial and ruling in cases that shaped the meaning of the postwar amendments. Stahr draws on extensive archival research to present Chase as a complex figure: ambitious to the point of scheming for the presidency even while serving in Lincoln's cabinet, yet genuinely committed to racial equality at a time when such commitment was rare. This biography fills a significant gap in the literature on the Civil War era and its aftermath.