  We review the remarkable relationship between the laws of black hole
mechanics and the ordinary laws of thermodynamics. It is emphasized that - in
analogy with the laws of thermodynamics - the validity the laws of black hole
mechanics does not appear to depend upon the details of the underlying
dynamical theory (i.e., upon the particular field equations of general
relativity). It also is emphasized that a number of unresolved issues arise in
``ordinary thermodynamics'' in the context of general relativity. Thus, a
deeper understanding of the relationship between black holes and thermodynamics
may provide us with an opportunity not only to gain a better understanding of
the nature of black holes in quantum gravity, but also to better understand
some aspects of the fundamental nature of thermodynamics itself.
