Children of Tomorrow
A. E. van Vogt
 Commander John Lane returns from a ten year mission in space to find that the teenagers of Spaceport City have organized themselves into "outfits", well disciplined, non-violent little gangs with their own customs and argot, and that the parent's role in teen upbringing has become minimal. His 16 year old daughter Susan belongs to the Red Cat Outfit, whose newest member Bud is actually a spy for the alien fleet that has secretly followed John Lane as he returned to Earth.