The Special Study format allows you to dig deeper by providing all the data needed (including game-map reference-numbers) to reconstruct the situation at any date in the Journal period. What it was like for everyone from diplomats to generals and common soldiers.
These books work well with the games, but the real point is when history lives instead of dead facts going nowhere.
Special Study, Nr. 1
1813: The Year that Doomed the Empire
The companion to Napoleon at the Crossroads and Four Lost Battles