Examining books by William Morris, J. R. R. Tolkien, and Ursula K. Le Guin, three of the most influential writers of the modern fantasy tradition, this book explores how fantasy writers engage with forest ecologies, histories and futures - both real and imagined - at a time when fantasies of a more sustainable society must be realised. Focusing on themes of escape, enchantment, experiment and engagement, this book demonstrates the significance of forest environments in the fantastic imagination, brings together ecocritical and fantasy scholarship in conversation with the environmental and social sciences, and examines the ways in which the fantastic imagination may be used as a creative form of environmental engagement today.