From the back cover:
The Great Houses of the Inner Sphere have created a new Star League to end the clan threat, launching an all-out attack against the most powerful Clan, Smoke Jaguar. During this campaign, the Inner Sphere was assaulted by a new and deadly creation: the ProtoMech. Swift and deadly, these half-size 'Mechs proved agile and difficult to destroy. Now, other Clans will quickly field this potent new weapon against the Inner Sphere, hoping to once more tip the balance of power in their favor.
BattleTech Technical Readout: 3060 provides descriptions, game statistics and complete rules for using the Clans' newest weapon in your BattleTech game: the ProtoMech. Additionally, new Inner Sphere and Clan BattleMechs and OmniMechs are included, as well as Clan vehicles.