RYDELL had taken a surveillance course, back at the academy, and his favorite part had been going out and following people. It wasn't something you did alone, but with at least one partner, and the more partners the better. You learned how to trade off, somebody taking your place, and how to deak up ahead of the subject so you'd be ready when the next guy needed to trade off. That way the subject never had the same person behind him for too long. There was a definite art to it, and when you got it down it was sort of like a dance.