Sách nói: Gray Lensman

Kimball Kinnison becomes a Gray Lensman. This name comes from the simple gray leathers these superior lensmen wear that has no insignia of any kind. They are unattached to any organization and as such can attack evil however they feel it best to do so. New training by Arisia gives him the sense of Perception which he uses to track and then eradicate the vile but powerful forces of Boskonia that are everywhere in the Galaxy. The Patrol is facing great danger now but with lensmen like Kinnison, they may hold their own or with luck, prevail. This is the fourth in the Lensman series, following the Galactic Patrol. - Summary by Phil Chenevert