Contemporary story of Arizona, with the emphasis on polo -- rules, history, team play -- rather than the boys about whom the story is told. It is set in a western ranch school, Ocotillo, where the forming of a polo team shares interest with camping trips in the mountains and bouts with horse thieves. Four boys and their horses are the pivot of the story -- the hero is 15, but there's interest here for any boy who is interested in horses, from 12 up. Fast-moving tale, with a new sport interest.