  A novel approach to electronic correlations and magnetism of crystals based
on realistic electronic structure calculations is reviewed. In its simplest
form it is a combination of the ``local density approximation'' (LDA) and the
dynamical mean field theory (DMFT) approaches. Using numerically exact QMC
solution to the effective DMFT multi-orbital quantum-impurity problem, a
successful description of electronic structure and finite temperature magnetism
of transition metals has been achieved. We discuss a simplified perturbation
LDA+DMFT scheme which combines the T-matrix and fluctuation-exchange
approximation (TM-FLEX). We end with a discussion of cluster generalization of
the non-local DMFT scheme and its applications to the magnetism and
superconductivity of high-Tc superconductors.
