  It is a common belief now that the explanation of the microscopic origin of
the Bekenstein-Hawking entropy of black holes should be available in quantum
gravity theory, whatever this theory will finally look like. Calculations of
the entropy of certain black holes in string theory do support this point of
view. In the last few years there also appeared a hope that an understanding of
black hole entropy may be possible even without knowing the details of quantum
gravity. The thermodynamics of black holes is a low energy phenomenon, so only
a few general features of the fundamental theory may be really important. The
aim of this review is to describe some of the proposals in this direction and
the results obtained.
