Check out CTLab’s reading list on Ethnographic Intelligence and Human Terrain Mapping.
At the same time, I’ll point out a reading list I’m putting together on the same topic (very draft at this time, subject to radical change and expansion), except it goes by the name of Public Diplomacy. We seem to forget that the bilateral nature of exchanges and information that is what was and is public diplomacy are essentially tools of intelligence. Cultural and educational exchange are the “slow” transmission and information activities are the “fast”, but both seek to provide intelligence on what the Other thinks, operates, and ticks and to provide the Other with insight into how you think, operate, and tick.
Don’t tell public diplomats this, they usually cringe at the suggestion. But that’s not how it always was.
The difference between the two lists is the scientific approach and methodology. One uses experts to dissect the mind of one side while the other strives to increase the awareness and knowledge of both sides about the other. One expert imparts deep knowledge versus having many people with qualified insights. Both are necessary, neither is fully supported.