‘S2’ is military parlance for the Intelligence Section, specifically at the Battalion level. Here’s a collection of books, documents, and manuals that should be on every Intelligence Officer’s bookshelf.
Learning to Eat Soup with a Knife: Counterinsurgency Lessons from Malaya and Vietnam. If you don’t understand popular support, then you don’t understand insurgency/counterinsurgency. This book was a must read before multiple deployments, and there’s a reason why it’s required reading among colonels, captains, lieutenants, and sergeants. There are too many important lessons in this book to not read it.
The S2’s Library is currently undergoing a major overhaul. Please check back later.