Differentiating individual foot types has decisive advantages in diagnosing and treating fallen arches and splayfoot. The basic methods of classifying different foot types are discussed and the necessity of such classifying is shown. Seemingly different interpretations of foot malformations are thereby explicable. Reference is made to the problem of therapeutic failures resulting from non-observance of the interaction between the arch-support and the shoes worn. The positive effects of indicated alterations in heel height are demonstrated.