  We present an interpolative method for describing coherent transport through
an interacting quantum dot. The idea of the method is to construct an
approximate electron self-energy which becomes exact both in the limits of weak
and strong coupling to the leads. The validity of the approximation is first
checked for the case of a single (spin-degenerate) dot level. A generalization
to the multilevel case is then discussed. We present results both for the
density of states and the temperature dependent linear conductance showing the
transition from the Kondo to the Coulomb blockade regime.
