Although the attacks of September 11 took place on American soil, the events of that day also resonated on a global scale. This chapter addresses major aspects of national systems of counterterrorism from around the world. Necessarily selective, this analysis focuses on important issues and themes that unite and differentiate national experiences in counterterrorism. The national systems of counterterrorism are reviewed in terms of the totality of their components and their interconnectedness. From this review, it should be possible to tease out the police dimensions in national systems of counterterrorism in relation to their variable political, legal, and other relevant components and, thereby, to draw some sensible conclusions on the global counterterrorism experience since September 11.