Wilderness is one of the most abiding creations in the history of religions. It has a long and seminal history and is of contemporary relevance in wildlife preservation and climate discourses. Yet it has not previously been subject to scrutiny or theorising from a cross-cultural study of religions perspective. What are the specific relations between the world’s religions and imagined and real wilderness areas? The wilderness is often understood as a domain void of humans, opposed to civilization, but the analyses in this book complicate and question the dualism of previous theoretical grids and offer new perspectives on the interesting multiplicity of the wilderness and religion nexus. This book thus addresses the need for cross-cultural anthropological and history of religions analyses by offering in-depth case studies of the use and functions of wilderness spaces in a diverse range of contexts including, but not limited to, ancient Greece, early Christian asceticism, Old Norse religion, the shamanism-Buddhism encounter in Mongolia, contemporary paganism, and wilderness spirituality in the US. It advances research on religious spatialities, cosmologies, and ideas of wild nature and brings new understanding of the role of religion in human interaction with ‘the world’.