Updated and re-formatted edition. John Shirley's Sci-Fi Thriller is finally back in print! A parasitic part of humanity since primitive times, they have been responsible for the worst human atrocities in history. When a psychology experiment goes out of control in remote Jasper, Oregon, the town swarms with Gray Pilots, whose stings bring out the cold-blooded killer in everyone and initiate an orgy of sociopathic slaughter.