What if your memory suddenly vanished? What if you could no longer summon up any recollections of your mother's embrace, a best friend's confidences, or the moment you first met your spouse? What if you couldn't even remember yourself, not your name, your school, where you worked, or even the face of the total stranger staring back at you from the mirror? If all of these memories were gone, would "self" even have a meaning? The truth is that while you may think of human memory as a capacity, a way to call up important facts or episodes from your past, it is much, much more. Your various memory systems, in fact, provide the continuity of consciousness that allows the concept of "you" to make sense, creating the ongoing narrative that makes your life truly yours. Without those systems and the overall experience of memory they make possible, you would have no context for the most crucial decisions of your life. You would have to make, without the benefit of experience and knowledge, the decisions that determine not only your quality of life, but your very survival. And your ability to learn, or even to form the personality that makes you unique, would similarly be set adrift.