The Earth Liberation Front is a radical environmental movement that developed from the ideological factionalization of the British Earth First! movement of the 1990s. Its ideological underpinnings are based in deep ecology, anti-authoritarian anarchism highlighting a critique of capitalism, a commitment to non-violence, a collective defense of the Earth, and a warranted feeling of persecution by State forces. In its current form, the Earth Liberation Front is a transnational, decentralized network of clandestine, autonomous, cells that utilize illegal methods of protest by sabotaging and vandalizing property. The small unit cells are self-contained entities that can operate without the support of external entities such as financiers or weapons procurers. Tactical and operational knowledge is developed and shared through commercially available books written by the broader environmental movement throughout the last four decades, as well as inter-movement publications produced by the cells and distributed through numerous sympathetic websites. Membership can be understood as occurring on two levels, the covert cell level and the public support level, both of which operate in tandem to produce and publicize acts of property destruction. At the cell level, individuals conduct pre-operational reconnaissance and surveillance, develop and construct weapons systems, carry out orchestrated attacks, and announce their actions to support groups and media while maintaining internal security and anonymity. At the aboveground level, support entities help to publicize attacks carried out by cells, respond to media inquiries and other public engagements, identify and coordinate aid to imprisoned cell members, and develop and distribute sympathetic propaganda produced by, and in support of affiliated individuals. This case study uses the history of the Earth Liberation Front’s United States attacks as its unit of analysis, and seeks to outline the ideology, structure, context and membership factors that constitute the movement.