Intelligence in War: Knowledge of the Enemy from Napoleon to Al-Qaeda

Keegan's historical overview makes me wonder how shifts in espionage techniques influenced the outcomes of key battles. Did any particular innovation stand out as a game-changer?

The book dives into detailed tactics, but I was surprised at how intricate some of the intelligence operations were. Were others expecting a more straightforward overview?

This timeframe covers such a wide range of warfare and intelligence development. I'm curious what motivated this particular scope and how the author connected these eras.