various
Deathwatch: Xenos Hunters

Drawn from the many Chapters of the Adeptus Astartes across the Imperium, the Deathwatch are an elite organisation dedicated to a single goal: the rooting out and extermination of all alien lifeforms with utter and brutal prejudice.
Warhammer 40k
anthology

It contains:
Exhumed
The Infinite Tableau
Last Watch
Weaponsmith
Rackinruin
Machine Spirit
Headhunted
A Sanctuary of Wyrms
The Vorago Fastness
The Alien Hunters
Fearful Symmetries