It is important that we know where we come from, because if you do not know where you come from, then you don't know where you are, and if you don't know where you are, you don't know where you're going. And if you don't know where you're going, you're probably going wrong.
Terry PratchettIt was a backwards memory of an event in his future so terrifying that it had generated harmonics of fear all the way along his lifeline.
Terry Pratchett