From the back of the book:
"How does a MechWarrior interface with a BattleMech? How does a ProtoMech really work? When was the Gauss rifle or the Particle Projector Cannon developed? Or how can I just make my own, cool and unique BattleMech design? If you’ve ever been plagued by these questions, then get on your coveralls and make sure you’ve got your astech certification, because you’re about to dive into BattleTech construction!
A companion volume to Total Warfare, the Classic BattleTech TechManual combines all the construction rules for the various units presented in that core rules set. Streamlined and updated, it contains all the core weaponry and equipment from previous rules set, as well as the newest, bleeding edge technologies. More than just a rulebook, however, the TechManual presents numerous sourcebook-style treatises, providing the in-universe context for these units and the technologies of their development. A must have resource for any BattleTech aficionado!"