  A survey of scientific and social activity of S. V. Vonsovsky is presented.
His fundamental works on the theory of electronic properties and magnetism of
transition and rare-earth metals and their compounds are reviewed. The
historical development of the many-electron polar (preceding the famous Hubbard
model) and $s-d(f)$ exchange (''Vonsovsky-Zener'', ''Kondo lattice'') models is
considered.
