Sendero Luminoso (Shining Path, or SL)

SENTRI (Secure Electronic Network for Travelers' Rapid Inspection)

September 11 Terrorist Attacks on the United States

Sequencing

Serbia, Intelligence and Security

Sex-for-Secrets Scandal

Ships Designed for Intelligence Collection

"Shoe Bomber"

Shoe Transmitter

Short-Wave Transmitters

SIGINT (Signals Intelligence)

Silencers

Skunk Works

Slovakia, Intelligence and Security

Slovenia, Intelligence and Security

Smallpox

Smallpox Vaccine

SOE (Special Operations Executive)

Soldier and Biological Chemical Command (SBCCOM), United States Army

Solid-Phase Microextraction Techniques

Soman

SONAR

SOSUS (Sound Surveillance System)

South Africa, Intelligence and Security

South Korea, Intelligence and Security

Soviet Union (USSR), Intelligence and Security

Space Shuttle

Spain, Intelligence and Security

Spanish-American War

Special Collection Service, United States