  We summarize the results for four-dimensional Bogomol'nyi-Prasad- Sommerfield
(BPS) saturated dyonic black hole solutions arising in the Kaluza-Klein sector
and the three-form field sector of the eleven-dimensional supergravity on a
seven-torus. These black hole solutions break $3\over 4$ of $N=8$
supersymmetry, fill out the multipletes of $U$-duality group, and the two
classes of solutions are related to each other by a discrete symmetry
transformation in $E_7$. Using the field redefinitions of the corresponding
effective actions, we present these solutions in terms of fields describing
classes of dyonic black holes carrying charges of $U(1)$ gauge fields in
Neveu-Schwarz-Neveu-Schwarz and/or Ramond-Ramond sector(s) of the type-IIA
superstring on a six-torus. We also summarize the dependence of their ADM
masses on the asymptotic values of scalar fields, parameterizing the toroidal
moduli space and the string coupling constant.
