Since the 1970s, three major philosophic perspectives have shaped radical environmental thought: spiritual ecologies, which are best illustrated by deep ecology; humanist ecologies, such as social ecology and eco-Marxism; and luddite ecologies, such as primitivism. On the ground, activism has often embraced a fusion of these perspectives as most Western radical environmentalism brings together a secular sacred regard for all living things with a materialist critique of Western civilization, particularly developments in technology and consumerism. In this chapter we introduce and examine the three major threads of radical environmentalism and provide an analysis of their philosophic strengths and weaknesses. We then argue that activists tend to fuse different aspects of these environmental philosophies together, sometimes intentionally and sometimes unintentionally.