It is the year 3145. Only thirteen years have passed since Gray Monday--the day that most of humanity's interstellar communications grid suddenly and mysteriously collapsed. Plunged into darkness and fearing the worst, the leaders and armies of the Inner Sphere scrambled to act, some fearing the approach of invaders, others seeking to exploit the chaos. Now, armies are on the march, war has erupted on every front, and the Republic of the Sphere--once a sign of mankind's hope for a brighter future--has retreated behind its fortress walls to prepare for the inevitable.
Field Manual: 3145 updates the military and political state of the Inner Sphere as it stands in the year 3145. This report includes a brief history and overview of recent developments in the BattleTech universe, as well as current TO&Es for the major 'Mech forces and mercenary commands employed by the realms and Clans of the Dark Age Inner Sphere. Special era-specific rules are also included, enabling players to create characters and forces for use in campaigns set in and after this critical point in BattleTech history.