Virtually all of us have experienced problems with sleep at some point in our lives. Sleep problems come in a variety of forms. Perhaps you’re unable to fall asleep, or maybe staying asleep is the problem, or perhaps you awaken unrefreshed two or three hours before you’d planned. The end result is that you’re tired the next day, or grouchy, or you can’t concentrate. And the next night arrives accompanied by that lurking fear: What if it happens again? Fortunately, most insomnia is transient, meaning that it clears up by itself.