For 150 years, the assassination of Abraham Lincoln has fascinated the American people. Relatively few academic historians, however, have devoted study to it, viewing the murder as a side note tied to neither the Civil War nor Reconstruction. Over time, the traditional story of the assassination has become littered with myths, from the innocence of Mary Surratt and Samuel Mudd to John Wilkes Booth's escape to Oklahoma or India, where he died by...