The wide applicability of the Langmuir-Hinshelwood classical kinetics to surfaces which are known to depart strongly from ideal Langmuir behavior is a well-known paradox of surface catalysis. The applicability and limitations of the classical method are illustrated by means of a simple reaction. The generality of the method is demonstrated by its applicability to ammonia synthesis with and without water vapor. The limitations are often more than compensated for by the added insight into reaction mechanism which it can provide without unded complexity. A three-step approach to surface kinetics is suggested and discussed.