By Michael Shermer

Charles Darwin and Adam Smith may seem like strange bedfellows, but bestselling author Michael Shermer finds the fathers of evolutionary theory and capitalism to be a perfect match. Our ancient ancestors first hung around in bands of a few dozen, cooperated only with kin, and fought with neighboring tribes. As our societal structures have changed drastically and personal worth has increased thousands of times over, our genes haven't had time to catch up to the ever-expanding global economy. For example, our tribal notions of altruism guide the way we feel about fairness, so we irrationally act as though others have our best interest in mind.

Drawing from research, and injecting his own wit, Shermer explains why people make bad decisions about money, why wealth can't buy you happiness, and why we love cooperating. "We cooperate for the same reason we copulate—because it feels good," he writes, noting that hormones associated with sexual reward are also released when people work together economically.

Modern Homo economicus still uses trade to turn enemies into friends, even on a grand scale: Since we've started trading more with China, diplomatic tensions have eased. As Shermer points out, "where Starbucks do not cross frontiers, armies will."

Smart Money: Three biases to avoid, from The Mind of the Market.

• Don't let the scale of a transaction sway you. A $100 gain is the same whether it comes from a $1,000 stock sale or pawning your old bike.
• Don't compare yourself to others. If the neighbors won $500 in a lottery and you won $5, you've still won, no matter how the profits match up.
• Beware the endowment effect: People tend to overvalue what they already own. Try to be objective when evaluating a sale price.

By Sonja Lyubomirsky

As pragmatic as a car manual, this how-to is anything but self-help fluff. Drawn from a career of rigorous research, Lyubomirsky's argument that 40 percent of our joy is within our control could convince the staunchest fatalist that happiness is both a choice and a lifelong endeavor. She explores 12 ways to exploit that slice, such as savoring pleasure, pursuing goals, and living in the present, and ends with a guide to sustaining your newfound contentment.

By John J. Ratey

From curing addictions and boosting memory to improving social skills and reducing violence, exercise benefits the brain in countless ways. Ratey, a Harvard psychiatrist, draws on hundreds of scientific studies and numerous success stories to make the case that exercise dramatically affects our minds. Motion not only shifts our brain chemistry, it changes the brain's structure by inducing neuron growth. If your goal is to heighten mental function, the clear path is the track.

By Brian Alexander

When Brian Alexander took the job of sex columnist for MSNBC, he was shocked by the imagination and intrepidity in his readers' letters. To get to the bottom of America's ever-growing fascination with kink, he hit the road. Over several months he visited a fetish convention, a swingers club, a bondage workshop, as well as sex-toy parties in the Midwest and a minister who advocates recreational nookie. Navigating each episode with both humor and reflection, Alexander sees exhilarating liberation but also a kind of "kitschy banality": Where's the excitement when our thrills are no longer taboo?