In the 1970s, it was thanks to the zealous efforts of the sustainability prophets that a new social phenomenon was born – the green movement. However, with the spate of industrial accidents in the 1980s, from Bhopal and Love Canal to Chernobyl and Exxon Valdez, the spotlight began to shift from wildlife conservation to industrial pollution. It was not until the politicians were enticed into the debate that sustainability became a mainstream concern. In 1992, 178 country leaders paraded on the world stage at the United Nations Conference on the Environment and Development in Rio de Janeiro, more familiarly referred to as the ‘Earth Summit’. Finally, by the 1990s, it had become clear that the environmental and social movements were here to stay and getting stronger by the year. The last decade of the twentieth century saw the green trend being backed by politicians, consumers, religious groups, community organisations and business. We are including here what we believe are a few of the more helpful attempts to develop sustainability criteria – guides to elephant spotting if you like.