From the back of the book:

Ravaged during the Succession Wars and poorly governed by paranoid Chancellors, the Capellan Confederation has languished at the mercy of its more powerful neighbours for centuries. However, the time of Xin Sheng has arrived. A new birth. The devious and brilliant Sun-Tzu Liao leads his people into a glorious era of national pride and prosperity. Through subterfuge and warfare, he is driven to reclaim everything the Confederation has lost.

BattleTech Field Manual: Capellan Confederation provides an in-depth look at the rising power of House Liao, including profiles on every Confederation regiment and the regiments of the newly conquered St. Ives Compact. Special rules reflecting the unique abilities of each regiment are included, along with new equipment and 'Mechs exclusive to the Capellan Confederation.

User comment:

This sequel to the earlier House Liao (The Capellan Confederation) follows the same format as the other BattleTech Field Manuals in that it focuses largely on the military structure of the Capellan Confederation before introducing a scattering of new equipment, 'Mechs, vehicles, a Warship and some Battle Armour.

While this sourcebook is out of print, it has been released in an electronic format by the new license holder, Catalyst Game Labs, making it much easier to get hold of than some of the other Field Manuals.