Description and analysis of the complex structure of enamel can be facilitated through the application of a system of hierarchical levels of structural complexity. Five interdependent levels are distinguished. These are the levels of: 1) crystallites, 2) prisms, 3) enamel types, 4) schmelzmuster, and 5) dentition. This system provides a basis for analysis of both variation of particular structures and variation of structural types throughout a mammal's dentition. Optimally, in wide ranging systematic and biomechanical studies, all levels of structural complexity should be considered, but lack of information about one level does not prevent significant analyses at other levels.