From the sexcapades of Bill Clinton to the unbelievable story of Hugh Grant and the prostitute; from the 15-year-old who weighs only 82 pounds but believes she's obese, to the professor who screams profanities at other drivers in snarled traffic--we wonder out loud, "What are they thinking?!" What drives so many apparently normal, intelligent people to act irrationally, harming themselves and others?

According to Sigmund Freud, such behavior may be caused by the "id," our built-in mental invitation to everything from dangerous fun to horrendous acts of irrationality. For popular psychology writer David Weiner, "id" stands for "Inner Dummy," the part of the brain that we must come to understand if we are ever to know why we do foolish, irrational, and compulsive things. Drawing on the groundbreaking theories of evolutionary psychology, Battling the Inner Dummy localizes the source of our irrationality in the limbic id-the most primitive part of our brain that endlessly thirsts for status, sex, territory, nurturance, and survival. "We become captured by these drives," Weiner says. "By understanding our Inner Dummy, we can avoid disasters in our own lives."

Along with sound advice from clinical psychiatrist Dr. Gilbert Hefter on how to handle our own Inner Dummies with built-in rewards and punishments, Weiner brilliantly interweaves delightful, imagined conversations with Freud and staffers at a mythical advertising agency, who have been given the assignment of communicating the nature of the id's irrationalities to the general public (e.g., t-shirts that say, "Would someone please fix my Inner Dummy before I fall in love with another idiot?" and a bathroom scale that allows you to weigh eight pounds less each time you use it).

This inviting, humorous romp with Inner Dummies who have made the news illustrates how we can apply "ID prevention" in our daily lives and includes all the major strategies science and medicine have developed over the years to counter Inner Dummies that threaten our well-being. See how well you're handling your own inner dummy by taking the quizzes at www.innerdummy.com.