From the introduction: The Bowman Arm is set in District 268 of the Spinward Marches, a region on the very outer fringe of the Third Imperium. This book gives an overview of the region and details one world within it. It stands alone as a game setting. However, this book is intended to be compatible with a series of supplements detailing the worlds of the cluster. Each of them stands alone, too, but the whole is a complete description of the region; it can play host to a multitude of adventures. Alternatively, any of the single-world books can be easily transplanted and used somewhere else, or in an entirely different game setting. This book ties in with the ongoing ‘Golden Age’ adventure series from Avenger Enterprises and is updated for use with Traveller Hero. The first of the Avenger adventures, Call of the Wild, takes place just outside The Bowman Arm, on Steel in the Sword Worlds subsector.