Scorn the alien. The members of the Ordo Xenos do all they can in order to keep the Imperium of Man just that... of Man. There are Orks that would love nothing more than to just Waaagh all over everything, Eldar who would love to regain some of the glory of their past, Dark Eldar who are always on the hunt for slaves, and Tyranids who just want to eat everything they can find. You'd think that in the far-off future of the 41st millennium, there was only war.
In Enemies Without, you and your other Dark Heresy players can join the Ordo Xenos and safeguard billions of human lives from the ravaging hordes of aliens that swarm throughout the galaxy. The book has detailed information about all sorts of alien threats. Of course, to fight off all those aliens, it'll take some new gear. There's plenty to be found within the pages. Fight fire with fire by turning the weapons of the aliens against them (though that chunk of metal that the Ork was firing a minute ago probably won't work for you, unless you believe really, really hard that it will. That's how it works for him).
This book will be hitting gaming store shelves in the 4th quarter of 2015.