  We explore the interplay between black holes in supergravity and quantum
field theories on the world-volumes of D-branes. A brief summary of black hole
entropy calculations for D-brane black holes is followed by a detailed study of
particle absorption by black holes whose string theory description involves
D-branes intersecting along a string. A conformal field theory with large
central charge describes the low-energy excitations of this string. The
absorption cross-sections give rise to greybody factors in Hawking radiation
processes which are characteristic of conformal field theory at finite
temperature.
  Particle absorption by extremal three-branes is examined next, with
particular attention to the implications for supersymmetric gauge theory in
four dimensions. A fascinating duality between supergravity and gauge theory
emerges from the study of these processes. Fields of supergravity are dual to
local operators in the gauge theory. A non-renormalization theorem of N=4 gauge
theory helps explain why certain aspects of the duality can be explored
perturbatively. Anomalous dimensions of a large class of local operators in the
gauge theory are shown to become large at strong 't Hooft coupling, signaling a
possible simplification of N=4 gauge theory in this limit.
