Intelligence organizations whose institutional structures, operational cultures, and histories shaped the discipline. Each entry examines the organization’s founding conditions, the tradition it belongs to, and what its institutional design reveals about the relationship between intelligence and the state it serves.
- Office of Strategic Services — the wartime organization that created American centralized intelligence
- Central Intelligence Agency — the OSS’s institutional heir and the Anglo-American tradition’s dominant organization
- National Security Agency — signals intelligence at industrial scale
- Secret Intelligence Service (MI6) — British foreign intelligence, the oldest continuous service
- Security Service (MI5) — British domestic security and counterintelligence
- KGB — the Soviet state security organization that defined the Russian tradition
- GRU — Soviet/Russian military intelligence, institutionally continuous since 1918
- Mossad — Israeli foreign intelligence and covert operations
- Stasi — East German state security, the most comprehensive surveillance state in history