Catalyst Game Labs have released several new BattleTech PDFs including the Era Report 3052.
From their website:
For three hundred years, the nations of the Inner Sphere waged war in the name of the fallen Star League, sending armies of MechWarriors into battle for glory and power. Yet even as BattleMechs clashed over the forgotten ruins of humanity’s Golden Age, the descendants of the long-lost Star League Defense Force gathered their might among distant stars.
Then, in 3048, amid reports of a technological renaissance in the Sphere, the leaders of Kerensky’s children decided the time for invasion had come. The Clan Invasion would transform the face of warfare and the fate of nations across the Inner Sphere, marking an all new era for all of humankind.
Era Report: 3052 describes the state of the Inner Sphere and the Clans at a pivotal period in BattleTech history: the early years of the Clan Invasion. Presented as a general overview of the period, rather than a focused report on a single conflict, this book includes descriptions of every major Inner Sphere and Clan faction. Notable personalities, military forces, and an overview of the technological capabilities of the Inner Sphere and Clan powers of this critical era in history are also provided, along with special advanced-level rules for campaigns set in this era, whether played using the Total Warfare core rules or those found in A Time of War: The BattleTech RPG.