Twilight Sparkle: None of those ponies had anything valuable enough to trade for my books. Not because these books belong to a princess, but because they helped make me who I am. Just like you said. This was the one I was so absorbed in the day Spike decided he owed Applejack a life debt. And this one reminds me of the day I got it – which was the day I met you. I may not ever need to read these again, but that doesn't mean they don't have value. I realize that now, thanks to you, Pinkie.