This thesis explores contemporary anarchism, in its re-emergence as a social movement and political theory over the past decade. Its method combines cultural sociology and philosophical argumentation, in a participatory research framework. The first part, "Explaining Anarchism", argues that it should be addressed primarily as a political culture, with distinct forms of organisation, of campaigning and direct action repertoires, and of political discourse and ideology. Largely discontinuous with the historical workers' and peasants' anarchist movement, contemporary anarchism has fused in the intersection of radical direct-action movements in the North since the 1960s: feminism, ecology, and the resistance to nuclear energy and weapons, war, and neoliberal globalisation. Anarchist ideological discourse is analysed with attention to key concepts such as "domination" and "prefigurative politics", emphasising the avowedly open-ended, experimental nature of the anarchist project. The second part, "Anarchist Anxieties", is a set of theoretical interventions in four major topics of controversy in anarchism today. Leadership in anarchist politics is addressed through sustained attention to the concept of power, proposing an agenda for equalising access to influence among activists, and an "ethic of solidarity" around the wielding of non-coercive power. Violence is approached through a recipient-based definition of the concept, exploring the limits of any attempt to justify violence and offering observations on violent empowerment, revenge and armed struggle. Technology is subject to a strong anarchist critique, which stresses its inherently social nature, leading to the exploration of Luddism, the disillusioned use of ICTs, and the promotion of lo-tech, sustainable human-nature interfaces as strategical directions for an anarchist politics of technology. Finally, the lens of the Israeli-Palestinian conflict is used to address anarchist dilemmas around national liberation, exploring anarchist responses in conflict-ridden societies, and direct action approaches to peacemaking.