The article traces some of the early efforts at institutionalizing cooperative law enforcement in Europe and examines more recent developments as they relate to, and are affected by, Maastricht and the Treaty of European Union (TEU). It describes emergent law enforcement structures, mandates, and operations; it analyzes their political repercussions and associated practical problems. Efforts at cooperative policing include: (1) The International Criminal Police Organization (“Interpol”), formed in 1923 to serve as a conduit for communicating and exchanging information about individual instances of traditional crimes on a case-by-case basis; (2) the Trevi Group, created in 1975 to ensure greater cooperation among European countries in combating terrorism; (3) the Schengen Agreements, formed in 1985 in an attempt to harmonize cross-border procedures to facilitate the movement of people and products, also had police powers over drugs, firearms and frontier surveillance; and (4) Title VI on the TEU, which encompasses activities ranging from immigration and international criminality to terrorism and customs regulations. References