Bad guys are not allowed to have birthdays, pick blueberries, or disturb the baby. So say the four-year-olds who announce life's risks and dangers as they play out the school year in Vivian Paley's classroom. Their play is filled with warnings. They invent chaos in order to show that everything is under control. They portray fear to prove that it can be conquered. No theme is too large or too small for their intense scrutiny. Fantasy play...