In 1900, Margaret Hossack, the wife of a prominent Iowa farmer, was arrested for bludgeoning her husband to death with an ax while their children slept upstairs. The community was outraged: How could a woman commit such an act of violence? Firsthand accounts describe the victim, John Hossack, as a cruel and unstable man. Perhaps Margaret Hossack was acting out of fear. Or perhaps the story she told was true-that an intruder broke into the house, killed...