From the back of the book:
ROLEPLAYING IN THE GRIM DARKNESS OF THE 41ST MILLENNIUM
You are a Guardsman, tithed from your homeworld alongside countless others to wage the God-Emperor’s war across the endless battlefields of the galaxy. It is your duty to drive back the horrors that threaten humanity from all sides. Despite the overwhelming odds stacked against your squad, you stand together, bound by a code of brotherhood and honour. You are the thin line that protects the Imperium from complete destruction. You are the Imperial Guard.
Play as one of twelve different Specialities, from the devastating Heavy Gunner and skillful Medic to the ruthless Commissar and brutish Ogryn. Then wade into battle alongside your squad of trusty comrades as you bring the God Emperor’s war to all who would oppose you.
Dynamic rules for all eventualities let you handle everything from social interaction to wading into battle alongside the deadly war machines of the Imperial Guard.
Comprehensive background on the Imperium, the Imperial Guard, and the war raging in the Spinward Front, written by Warhammer 40,000 Novelist Andy Hoare.
Plunge your players into the chaos of war with an introductory adventure that puts them right in the heart of the action.
The Only War core rulebook contains everything you need to start your adventure in the Warhammer 40,000 universe.