Teachers, especially prospective teachers, often react negatively to a discussion of principles. Instead, they seek specific formulae that they may invoke to cope with any given classroom situation. The desire is to gather a store of reactions "guaranteed to work." If situation A occurs, they apply reaction B and get result C. If they learn all the proper responses, they are assured of success in teaching. While such feelings are understandable, they are quite unrealistic. The same lesson plan that produces gratifying results with the nine-o'clock class may be a tragedy at ten o'clock. The teacher who stimulates some students may be a failure with others. The procedures that work one year may be unproductive the next. Surefire formulae simply do not exist. If foolproof recipes were available, teaching would cease to be the exciting, stimulating profession that it is. The best that classroom teachers can do is to adopt a set of guidelines with which they can operate in a flexible fashion.