Some new and for pre-order, some old and available for the first time via epublishing.
From the announcement:
Interstellar Expeditions: Interstellar Players 3 describes the organization and efforts of Interstellar Expeditions as it continues to search within (and beyond) human-occupied space in the BattleTech universe. First introduced in Interstellar Players, IE’s operations have now gone truly universal, seeking answers and treasures not only from the lost and forgotten worlds of humanity’s distant past, but also the distant colonies and civilizations that have risen—and even fallen—beyond the boundaries of the Inner Sphere. Gamemasters and players can decide which of these groups and discoveries may actually bear fruit, and which are the misdirections left behind by the surviving leaders of the Blakist war machine. Whether from this sourcebook or the gamemaster’s own imagination, these discoveries can become the ultimate villain, ally, or unique new setting for any type of BattleTech campaign!