This course addresses counterterrorism in the United Kingdom. Tracing the UK response to violent subnational terrorism back to its efforts against the PIRA in the 1970s through the 1990s, the course modules demonstrate how the UK counterterrorism community recognized long ago the serious threat to national security that subnational violence poses, and how its response to the recent violent terrorist activities of al-Qaeda and ISIS is situated within an environment informed by the earlier “Irish Troubles.”