An excellent addition to Rogue Trader, providing a whole host of creatures and races to use in games (along with some some good rules for building new ones). It's a shame that some of the iconic creatures of the 40K universe were not included (where are the Genestealers!?!?!?) but we do get expanded rules for Orks, Eldar and demons.
As always, excellent art and writing which you expect for a product that has such a wealth of material to draw upon.
[4 of 5 Stars!]