BattleTech is a game that I have played probably less than ten times in my life. I had a friend that was really into it and he insisted I try it. I own an amazing amount of the stuff for not ever having played it all that much. I am a sucker for technical manuals and much of what I own falls into or close to that category. That and I seem to be willing to buy almost anything gaming related.
From the back of the book
The BattleTech Tactical Handbook is an advanced-rules supplement for the BattleTech game universe. The Handbook provides advanced rules and equipment that enable players to add new depth and intensity to their games. Guidelines for creating long-term campaigns and double-blind games, formulas for calculating the combat values of all BattleTech combat units, detailed descriptions of advanced weapon systems and more make the BattleTech Handbook a necessity for the serious BattleTech player.