Licensed to Practice begins with an 1891 shooting in Wheeling, West Virginia, that left one doctor dead and another on trial for his life. Formerly close friends, the doctors had fallen out over the issue of medical licensing. Historian James C. Mohr calls the murder -a sorry personal consequence of the far larger and historically significant battle among West Virginia's physicians over the future of their profession.-

Through most of the nineteenth century, anyone could call themselves a doctor and could practice medicine on whatever basis they wished. But an 1889 U.S....