This is the paperback Kill Team supplement originally found in the Kill Team: Shadowvaults boxed set, now available on its own. Inside these 120 pages, you'll find full rules and background for both the elite Kasrkin and calculating Hierotek Circle kill teams, datacards (including fillable blanks to copy), Tac Ops and Ploys, equipment lists, and Spec Ops rules including Rare Equipment and Battle Honours.
Also contained within is a lore guide to the shadowy depths of the Gallowdark, Close Quarters rules for fighting in space hulks, full killzone rules for using the Gallowdark terrain set alongside Shadowvaults terrain pieces, and the Shadow Operations: Shadowvaults Mission Pack and Critical Operations: Gallowdark Mission Pack, which together offer 18 missions and stealthy Infiltration rules for use in your games of Kill Team, playable with any faction.
You'll need a copy of Warhammer 40,000: Kill Team Core Book to make full use of this supplement.