  Correlation computations on multiband Hubbard Hamiltonians are presented. It
is shown why the proper degeneracy is of vital importance and that the atomic
exchange interaction plays a particular role. The different methods are
connected, and their results are discussed. Many experimental properties for
the elemental solids can be explained by single closely related sets of
parameters each. There is an exception, Tc of Fe. Here, a novel feature of
longer-range interactions enters, as demonstrated on ab-initio results of the
Local Ansatz for Fe. Connections are made to LSDA-calculations; and their
seeming successes and deficiencies are explained.
