Soft and stroking, firm and embracing, fast and strong, hard and sharp -- the effect of a touch is so powerful that just imagining someone moving hands across your body can make you purr with pleasure, squeal with delight, sigh with relief or recoil with pain. Our sense of touch is the first to develop and is connected with every other sense: taste, hearing, sight and smell. Together, they tell us what is going on in the world and inside our own bodies. These days, what lovers, parents, poets and athletes have always suspected about the emotional and physical benefits of touch, scientists are analyzing and identifying. Here are some of the wonders they are discovering.