In recent years environmental scientists have focused on the co-called
Critical Zone, where landscapes are treated as integrated systems that
encompass bedrock, soils, water and sky and are teeming with life. The
concept is intriguing to young minds, exploring the natural world in an
integrated way that has not been imparted often in children's
literature. This book discusses how rocks become soil, movers of the
Critical Zone such as gophers and other burrowers, how plants provide
food and habitats for insects, birds, and animals, how the water cycle
functions, the process of photosynthesis, and how humans are part of
this vast system. In sum, it explains how all of life can be found in a
thin outer layer called the critical zone.