  Fundamental string theory has been used to show that low energy excitations
of certain black holes are described by a two dimensional conformal field
theory. This picture has been found to be extremely robust. In this paper it is
argued that many essential features of the low energy effective theory can be
inferred directly from a semiclassical analysis of the general Kerr-Newman
solution of supersymmetric four-dimensional Einstein-Maxwell gravity, without
using string theory. We consider the absorption and emission of scalars with
orbital angular momentum, which provide a sensitive probe of the black hole. We
find that the semiclassical emission rates -including superradiant emission and
greybody factors - for such scalars agree in striking detail with those
computed in the effective conformal field theory, in both four and five
dimensions. Also the value of the quantum mass gap to the lowest-lying
excitation of a charge-$Q$ black hole, $E_{gap}=1/8Q^3$ in Planck units, can be
derived without knowledge of fundamental string theory.
