  We derive the supersymmetric low-energy effective theory of the D-flat
directions of a supersymmetric gauge theory. The Kahler potential of Affleck,
Dine and Seiberg is derived by applying holomorphic constraints which
manifestly maintain supersymmetry. We also present a simple procedure for
calculating all derivatives of the Kahler potential at points on the flat
direction manifold. Together with knowledge of the superpotential, these are
sufficient for a complete determination of the spectrum and the interactions of
the light degrees of freedom. We illustrate the method on the example of a
chiral abelian model, and comment on its application to more complicated
calculable models with dynamical supersymmetry breaking.
