Although rare before the mid-1980s, federal-local law enforcement collaboration has grown rapidly as local police and prosecutors have worked closely with federal authorities to address increased levels of drug trafficking and violent crime. This Research in Brief examines the rise of federal-local collaboration, the various types of collaborations such as task forces and grant-funded programs, and the advantages collaboration offers both local and federal authorities. Despite some observers' concerns about the "federalization of crime," most partnerships have been characterized by restraint, careful coordination, and shared operational leadership. Researchers found that collaboration has become institutionalized in many U.S. cities and is likely to expand in the future.