The Second Succession War is a Historical type source book, which was written in the style of a Terran document. It was done originally as in-universe drafted first written in year late Dark Age Era and posed to be a published a nearly century after being written in which it is looking back to events of the Second Succession War.

The book reveals the details of the Second Succession War, in which all the major interstellar nations of the Inner Sphere would exhausted themselves trying take power with all their might in a second attempt conquer former Star League. With only a brief moment of uneasy peace after the First Succession War, the book chronicles the second act of destruction and it reveals ComStar's secret rise of power behind the curtains of intrigue to attempt to steer the Inner Sphere to technology downswing so they may take power.

Second Succession War gives detail accounts of the conflict that would continue to ravage the Inner Sphere and herald it's civilization into the brink destruction.

The book includes; Rules creation of scenarios based on the events of the book, profiles of individuals who were major characters during the war and Conversion rules into various forms of Battletech Gameplay such as Interstellar Operations's Abstract Combat System, Inner Sphere at War, and Strategic BattleForce. Also found in this book is a Mini-Battletech Technical Readout of units once featured in the original Technical Readout: 3025 and later Technical Readout: 3039 with new images formerly known as Unseen.