‘Some key concepts’ focuses on the key concepts widely held and pivotal to thinking about environmental ethics. It begins with the concept of nature, ways in which people seek to relate nature to human behaviour, and attitudes both to the nature that surrounds us and to our inner nature too. Are human beings apart from nature or simply part of nature? It then discusses the concept of the environment. Only through the concept of the environment as an objective natural system can we make sense of environmental problems in the first place. The next key concepts considered are moral standing and value, which introduce the ethics of biocentrism and ecocentrism.