As they all said - nothing remotely related to the game play. The Universe though is quite there. Death Angel was recommended - Chaos in the Old World is also a noteworthy choice though it's the Warhammer Fantasy universe and not 40k.
Also, Death Angel the card games gives a good intro to a title I'm surprised no one has mentioned yet - Space Hulk.
Also, Death Angel the card games gives a good intro to a title I'm surprised no one has mentioned yet - Space Hulk.