For weeks in 1902 it commanded headlines. All of Wyoming and much of the West followed the trial of Tom Horn for the murder of a fourteen-year-old boy. John W. Davis's book, the only full-length account of the trial, places it in perspective as part of a larger struggle for control of Wyoming's grazing land. Davis also portrays an enigmatic defendant who, more than a century after his conviction and hanging, perplexes us still.

Tom Horn was one of the most fascinating figures in the history of the West. Employed as a Pinkerton and then as a range detective, he had a...