Like Osprey's military history books, the HR series contain the general history on a topic. Readers are given time lines and other background information on the historical narrative. These books are geared more toward Dungeon Masters, but player should find them interesting, too. Each book also features a short bibliography for further reading.
The bibliographies have some solid historical sources, both primary and secondary. Today I get a kick out of going through these bibliographies. "Hey, I've read that!" "Hey, I know that author!"
The caveat: The AD&D Historical Reference Sourcebooks were never meant to be scholarly works, even less so than Osprey. Don't cite them in your paper, even at the K-12 level. Still, I think its important that gamers, and people in general, get more exposure through history, even if it is through a game.
I know these historical reference books have influenced me into being more interested about history. And I know that the three books above had some influence on the Domikka Campaign Setting.
In the future, I'll review each of these books. I've listed them below.
But for now: What do you think of these books? Have you run any campaigns set in The Glory of Rome or fought to take Jerusalem in The Crusades? Or did you take ideas from them, such as plucking the black powder rules from A Mighty Fortress and put them in your game?
HR2: Charlemagne's Paladins
HR4: A Mighty Fortress
HR5: The Glory of Rome
HR6: Age of Heroes
HR7: The Crusades