In the new millennium, as environmental alarm has escalated, so has interest and concern about the role of religion in nature. Much of the thinking has involved a hope for a 'greening' of religion – i.e. that religion might promote environmentally protective action. Many believe that this 'greening' of religion is a prerequisite for solving the world's social and environmental problems. Curiosity regarding the relationships between human culture, religion and the wider natural world, however, goes beyond such curiosity. The ERN represents an intensive effort to broaden the inquiry and asks the fundamental question: What are the relationships between Homo sapiens, their diverse religions, and the earth's living systems--The answers are difficult and complex, intertwined with and complicated by a host of social, environmental, and religious variables. The goal of the ERN is to explore this question in a way that illuminates these relationships without engaging in wishful thinking, irrational pessimism, or the tendency to oversimplify the dynamic, sometimes rapidly evolving relations between humans, their religions, and the natural world. Encyclopedia of Religion and Nature shows convincingly that religion has a great deal to do with nature, nature a great deal to do with religion, and both have everything to do with the planetary future.