Ever wonder how the Earth's climate has changed over the entire course of Earth's history? In this book, the author displays these records over multiple time frames, and then attempts to explain why the average surface temperature has moved in the way that it has throughout each. By reviewing the many physical processes that drive climate change, the reader becomes aware that the Earth's average surface air temperature is primarily the product of two variables - heat from the Sun and heat from the Earth. Fusion from Above and Fission from Below.