Before the Civil War, George Proctor Kane had been a businessman, thespian, political appointee, philanthropist and militiaman. During the war, as Baltimore's chief of police, he harbored the divided loyalties familiar to the border states--Southern in his sentiments yet Northern in his allegiances. As the city's top lawman, he sought to reform Baltimore's "Mobtown" image. He ensured President-Elect Lincoln, passing through on the way to his inauguration, was not assassinated. He protected Union troops marching to defend Washington, D.C. He was eventually imprisoned as a Southern sympathizer,...