The 1990s seen a remarkable increase in appreciation of the links between the state of ecosystems and the state of humankind. This publication explores the key global issues of biodiversity. It examines the relationships between humankind and biodiversity, covering salient features of human impacts on the environment from the earliest hominines onward, and the uses currently made of elements of biodiversity. The text looks at the trends in condition of the main ecosystem types and the species integral to them and outlines some fundamental aspects of material cycles and energy flow in the biosphere.