From the back of the book:
"In 3055, a new breed of Inner Sphere BattleMech started rolling off assembly lines- specifically designed to counter the Clan Invasion-while additional second-line Clan 'Mechs began to appear. Now, twelve years later, those designs have become a staple of the modern battlefield, giving rise to notable MechWarriors and new variants, while the demands of the ever-popular Solaris VII Games has resulted in a plethora of new dueling 'Mechs using prototype technology.
For the first time, Classic BattleTech Technical Readout: 3055 Upgrade? presents 'Mechs built using technology from MaximumTech, Revised?, as well as MapPack: Solaris VII?. Upgraded in appearance and technology, the designs first presented in the Solaris VII box set and Solaris: The Reaches are now back in print, along with several new Solaris VII designs. Additionally, as well as the upgraded appearance of selected Clan designs, all the art work for Technical Readout: 3055 Upgrade is new, providing fresh illustrations of now classic Inner Sphere BattleMechs."