Special reconnaissance (SR) is conducted by small units, such as a recon team, made up of highly trained military personnel, usually from special forces units and/or military intelligence organizations. Special reconnaissance teams operate behind enemy lines, avoiding direct combat and detection by the enemy. As a role, SR is distinct from commando operations, but both are often carried out by the same units. The SR role frequently includes covert direction of airstrikes and indirect fire, in areas deep behind enemy lines, placement of remotely monitored sensors, and preparations for other special forces. Like other special forces, SR units may also carry out direct action and unconventional warfare, including guerrilla operations.

Human intelligence is intelligence-gathering by means of human sources and interpersonal communication. It is distinct from more technical intelligence-gathering disciplines, such as signals intelligence (SIGINT), imagery intelligence (IMINT), and measurement and signature intelligence (MASINT). HUMINT can be conducted in a variety of ways, including via espionage, reconnaissance, interrogation, witness interviews, or torture. Although associated with military and intelligence agencies, HUMINT can also apply in various civilian sectors such as law enforcement.