The world isn't coming to an end, contrary to what you may have heard, says Jurriaan Kamp. And pessimism can be fatal: Kamp cites research showing that those who indulge in negative thinking are more likely to smoke, be overweight, and have high blood pressure, high cholesterol, and an increased risk of Parkinson's disease. Meanwhile, evidence abounds that optimism-intelligent optimism, not a rose-colored-glasses brand of wishful thinking-is good not only for your mind but for your body, too. He explains how we can cultivate an outlook of informed optimism that will make our lives and the world better.