Mechanical engineers have developed a system that greatly decreases the amount of toxic hydrocarbons a car releases. (p. 206)

Giving patients placebo pills for a week before they begin to participate in trials of antidepressants can help clinicians gauge how well they will respond to the actual medication. (p. 142)

In two studies, AIDS clinicians found that standard three-drug regimens fight HIV as well as four-drug treatments do, and that a single drug might maintain a patient's health once the virus is suppressed. (p. 115)

Research in rats shows that an experimental drug completely regenerates parts of the brain crucial to forming memories. (p. 101)

African Americans reduced the racial gap on IQ-test scores by about one-third between 1972 and 2002. (p. 85)

The remarkably successful cancer drug imatinib might cause heart failure in some patients. (p. 69)

Obese adults are 25 percent more likely than normal-weight adults to develop one of four mood or anxiety disorders. (p. 78)

The suicide rate among people with a psychiatric disorder that causes them to perceive themselves as ugly is higher than that among people with major depression. (p. 52)

When punishing criminals, people tend to seek retribution, not deterrence. (p. 61)

People who smoke light cigarettes are much less likely to quit smoking than people who smoke regulars. (p. 20)