Unlock the secrets of the Earth's natural history, from the planet's beginnings four and half billion years ago. Discover how the land and the oceans took shape, and how our world is constantly changing as a result of human actions and natural forces. Understand the Earth's place within the Solar System and the deeper Universe. Journey across the galaxies to discover the mysteries of deep space.This 80-page reference guide pulls together the very best material from the following individual titles in the highly successful Navigators information book series: Planet Earth and Stars and Planets. There are 16 Navigators titles in all, covering topics from history, geography, the natural world, and technology.