Equation for Evil

This one certainly doesn't deserve to be out of print. Loosely based on the story of Stockton, CA mass murderer Patrick Purdy, Equation for Evil is an excellent read. Caputo must have done some reading in neuroscience before writing the novel, but I got the feeling that he couldn't quite figure out where to go with the book's central theme -- whether the roots of evil are spiritual, biological, or both. Much is made of this issue in the first half of the novel, but it sort of fades out towards the end as the book takes on the shape of a conventional thriller. One of the book's major characters, psychiatrist Leander Heartwood, rather unconvincingly sheds his belief that the roots of violent behavior are in the brain and decides that evil is "a choice." Perhaps so, but the choice to open fire on a group of schoolchildren is not one that most of us would remotely contemplate, leaving the question of what makes people like Purdy tick hanging.Having done some reading and writing about neuroscience issues myself, I can empathize with Caputo's confusion, but research conducted in the years since this book was published has drawn even stronger connections between neurological abnormalities and violent behavior. I have spent a great deal of time thinking about the implications of all this and remain somewhat baffled. Seems like Mr. Caputo had a similar reaction.