A Wrinkle In Time! How could I forget it? Probably wasn't on my list because I've only read it once, way back when I was nine, and so it doesn't really qualify. But it probably would if I'd had a copy all these years. Twisted logic there, but it kind of works. <g>
Anyway, I remember being absolutely blown away with this one at the time, filled with wonder at the revelation of the ending. Which seemed awfully profound to me at that point. <sigh>
I really need to try and build up a collection of Madelaine's stories, I think. Thanks for the reminder, Breanna!