What can we make of the inexpressible joy of children? It is a kind of gratitude, I think--the gratitude of the ten-year-old who wakes to her own energy and the brisk challenge of the world. You thought you knew the place and all its routines, but you see you hadn't known. Whole stacks at the library held books devoted to things you knew nothing about. The boundary of knowledge receded, as you poked about in books, like Lake Erie's rim as you climbed its cliffs. And each area of knowledge disclosed another, and another. Knowledge wasn't a body, or a tree, but instead air, or space, or being--whatever pervaded, whatever never ended and fitted into the smallest cracks and the widest space between stars.