Postmodernity, as a logic of differentiation, heterogeneity, and flux not only gives impetus to new struggles of emancipation, but, perversely, also defines a new field of power and domination which these struggles must contend with. The question of power has always been central to radical politics. This chapter examines the concept of power, arguing that an understanding of modern power relationships and the new forms of ‘postmodern’ social control and surveillance that are emerging today — particularly in the ‘war on terror’ — is vital to the development of new radical political strategies. It takes as its point of departure Michel Foucault's notion of power, whose general focus on ‘micro-political’ relations tends to imply a kind of localised politics of resistance and, moreover, neglects to some extent the ‘broader picture’ of political domination, including the problem of state sovereignty itself. Finally, the chapter considers the ‘micro-physics’ of power, war and biopolitics, the sovereign state of exception, and the global ‘security’ state.