I review the classical and quantum properties of the (2+1)-dimensional black
hole of Ba{\~n}ados, Teitelboim, and Zanelli. This solution of the Einstein
field equations in three spacetime dimensions shares many of the
characteristics of the Kerr black hole: it has an event horizon, an inner
horizon, and an ergosphere; it occurs as an endpoint of gravitational collapse;
it exhibits mass inflation; and it has a nonvanishing Hawking temperature and
interesting thermodynamic properties. At the same time, its structure is simple
enough to allow a number of exact computations, particularly in the quantum
realm, that are impractical in 3+1 dimensions.Comment: LaTeX, 34 pages, 4 figures in separate fil
