Scientists began tracking the health of 268 Harvard sophomores in 1938 during the Great Depression. What they've found is this: our relationships and how happy we are in our relationships has a powerful influence on our health. Close relationships, more than money or fame, are what keep people happy throughout their lives, the study revealed. Those ties protect people from life’s discontents, help to delay mental and physical decline, and are better predictors of long and happy lives than social class, IQ, or even genes. Maybe the Beatles had it right: All You Need is Love.