The Imperial Guard
Codex: Adeptus Arbites
Language and Technology of the Imperium
The Emperor
Timeline of the Imperium
The Imperium Now
Worlds of the Imperium
The Galaxy, Space Travel, and The
Astronomicon
The Galaxy of the 41st Millenium
Venenum Assassin
Cullexus Assassin
Bishop of Metallica
Brother Captain Stern
Back to Warhammer 40,000 3rd Edition.
For more information from Rogue Trader, check out this great site:
The Astronomicon.