Supersymmetric black holes provide an excellent theoretical laboratory to
test ideas about quantum gravity in general and black hole entropy in
particular. When four-dimensional supergravity is interpreted as the low-energy
approximation of ten-dimensional string theory or eleven-dimensional M-theory,
one has a microscopic description of the black hole which allows one to count
microstates and to compare the result to the macroscopic (geometrical) entropy.
Recently it has been conjectured that there is a very direct connection between
the partition function of the topological string and a partition function for
supersymmetric black holes. We review this idea and propose a modification
which makes it compatible with electric-magnetic duality.Comment: 5 pages, based on talk given at the 11th Marcel Grossmann meeting,
Berlin, July 23-29, 200