In this paper a theory of relations and corelations between the lattice of fuzzy subsets of a crisp set X and that of a crisp set Y is developed, based on the theory of relations and corelations between textures. In a series of examples it is shown that these notions generalize in a natural way the impotant concept of fuzzy relation from X to Y . Difunctions are also characterized and their relationship with known mappings between fuzzy sets is investigated.