Life has shaped the Earth, and the Earth has moulded the history of life. That history, the co-evolution of our ancestors and their horne, has much to teach us about our place on the planet today. We are part of the fabric of the biosphere. As we change that fabric we would be wise to understand how our horne was built. Our planet is neither a hotel nor a colony. It is not a place which life briefly inhabits during a transient occupation. Instead, it is our horne, designed by the deeds of our ancestors and suited to our own needs. The history of life on Earth is held in the geological record, which is composed of the rocks, water and air that are available for study on the planet's surface. These rocks, the oceans and the atmosphere are not simply stores of information for the excitement of fossil hunters and geochemists, or resources to exploit without thought. Their cre­ ation and continued existence form an integral part of the development and management of the Earth as the horne of life.