  We present the list of irreducible (generalized) highest weight modules over
the Virasoro algebra and N=1 super-Virasoro algebras obtained as factor-modules
of (generalized) Verma modules. We present also the character formulae of all
these modules and single out the unitary irreducible ones. Most formulas are
valid for the three algebras under consideration, the different cases being
distinguished by two parameters. This is a slightly extended version of an
Encyclopedia entry.
