  The standard Einstein-Maxwell equations in 2+1 spacetime dimensions, with a
negative cosmological constant, admit a black hole solution. The 2+1 black hole
-characterized by mass, angular momentum and charge, defined by flux integrals
at infinity- is quite similar to its 3+1 counterpart. Anti-de Sitter space
appears as a negative energy state separated by a mass gap from the continuous
black hole spectrum. Evaluation of the partition function yields that the
entropy is equal to twice the perimeter length of the horizon.
