During the 1940s and 1950s, tens of thousands of Americans underwent some form of psychosurgery; that is, their brains were operated upon for the putative purpose of treating mental illness. From today's perspective, such medical practices appear foolhardy at best, perhaps even barbaric; most commentators thus have seen in the story of lobotomy an important warning about the kinds of hazards that society will face whenever incompetent or malicious...