Field Manual: 3145 is the next installment of the Field Manual series set in the latter years of the Dark Age Era first described by WizKids' MechWarrior collectible miniatures game.

This sourcebook provides a complete summary of the military readiness of the various factions in the BattleTech universe in the year 3145, shortly after the events described in Steven Mohan's Bonfire of Worlds epub novel, when the various factions of the Inner Sphere battle one another around the crumbling remains of the Republic of the Sphere.