In this paper, a classification of the regular embeddings of Kn,n, where n = 2e is a power of two, is completed. The number of such regular maps is one or two for e = 1, 2, respectively. For e ≥ 3 there are 2e−2 + 4 regular embeddings of K2e,2e . The method is based on classification of groups G which factorise as a product of two cyclic groups G = XY of order n such that the cyclic factors are...