The Campaign Companion contains rules for generating and running any type of force within the BattleTech universe. From a single pirate BattleMech all the way to regimental combat teams, players can scale to their own taste. Additional rules cover running campaigns, from battlefield roles and force-building, to missions and the Chaos Campaign system. Expanded OpFor rules allow for the easy generation of large-scale forces that mesh with the deployments from the dozen Field Manuals published over the years. Finally, complete solar system construction rules allow players to tailor their campaigns even further with unique worlds to defend or conquer!

The book completes the series begun by Total Warfare, as well as the "spine mosaic" depicted by the full set.