The Black Crusade Game Master's Kit is a serviceable aid to any Black Crusade campaign. It contains a fairly well-developed and lengthy campaign by Warhammer 40k RPG standards, focusing on the heretics seeking out treasures and power in a warp-ravaged world that still manages to have some semblances of the destitute normality one would see in Imperium worlds, and thus quite a lot of potential for roleplay. However, the sections with actual aid for GMs beyond the module, while it does contain important rules that increase the (somewhat lacking) longevity of Black Crusade player characters in comparison to the other RPGs, are short, and much of the material feels unambitious compared to the GM aids for the other lines. It is a worthwhile product, but if you're never going to look at the adventure module its value is greatly reduced.
[4 of 5 Stars!]