Book excerpt: In this gorgeous companion to the acclaimed Over and Under the Snow and Up in the Garden and Down in the Dirt, Kate Messner and Christopher Silas Neal bring to life a secret underwater world. In this book, readers will discover the plants and animals that make up the rich, interconnected ecosystem of a mountain pond. Over the pond, the water is a mirror, reflecting the sky. But under the pond is a hidden world of minnows darting, beavers diving, tadpoles growing. These and many other secrets are waiting to be discovered...over and under the pond.