Environmentalism is a contest about the meaning of nature and the social construction of activism, deviance and harm. The contests that are the subject of this book are fought on the margins, in spaces where what is deviant and what is criminal are fluid concepts. Forest activists engaged in Tasmania's old-growth forests, and Sea Shepherd Conservation Society activists campaigning in the Southern Ocean to protect whales tell powerful and moving stories about their encounters with nature. These are profound experiences that fundamentally alter how they understand themselves and their world. What emerges in this book is a perspective that recognises the personhood of non-humans and which gives rise to a strong moral obligation to defend nature from harm. Providing a unique account of environmentalism, one that highlights the voices of the activists and the nature they defend, Radical Environmentalism: Nature, Identity and More-than-human Agency will be of great interest to students and academics of green criminology, environmental sociology and nature-human studies more broadly.