Time dims memory. But not that kind. Somewhere in a corner of the brain, one little cell never forgets. It keeps the song that, heard again, recreates the room, the person, the moment. It preserves the phrase or the laugh or the gesture that resurrects a friend long gone. It knows precisely where you were and what you were doing when you heard about Pearl Harbor if you're old enough, or Kennedy's assassination, or Martin Luther King's, or the Challenger explosion. Every detail is frozen in memory, despite all the years. It keeps the innocuous question, too. The question that sometime later, when all the synapses are working, produces the epiphany, the moment when you're driving along and you realize that finally you understand. And why did it take you so long?