From the introduction:

This supplement to the Fifth Wheel - BoWM contains the profiles of known reprobates and renowned lawmen who live on the Edge, as well as community sketches, a map of the area, and a few other surprises besides.

Frontier Edge is a little slice of Shield Gate. Specifically, it’s the little slice that borders the Eastern Range. As a result, it’s the designated frontier of West Marque, the front line of the glorious conquest. While most of the natives are decent, hard working folk, the frontier has more than its fair share of outlaws, dirt riders, and disreputable low lives. They come in many forms - burly men, pretty doxies, weathered gents, and lady battleaxes - the type that’d scare a randy bull with a bur in its tail.