Tradecraft

Tradecraft, within the intelligence community, refers to the techniques, methods, and technologies used in modern espionage (spying) and generally as part of the activity of intelligence assessment.

This includes general topics or techniques (dead drops, for example), or the specific techniques of a nation or organization (the particular form of encryption (encoding) used by the National Security Agency, for example).

In the books of such spy novelists as Ian Fleming, John le Carré and Tom Clancy, characters frequently engage in tradecraft, e.g. making or retrieving items from "dead drops", "dry cleaning", and wiring, using, or sweeping for intelligence gathering devices, such as cameras or microphones hidden in the subjects' quarters, vehicles, clothing, or accessories.

This Mark IV microdot camera could be used to take pictures of documents. The microdot film was so tiny it could be hidden in a spy's personal effects and smuggled out of a location.
Caltrop used by the US Office of Strategic Services . When scattered on a roadway or runway, the hollow spikes puncture self-sealing rubber tires. The hole in the center allows air to escape even if the other ends of the tube are sealed by soft ground.
"Belly-buster", a hand-cranked audio drill strapped to an agent's stomach. It was used during the late 1950s and early 1960s to covertly drill holes into masonry for implanting audio devices, such as microphones.