  We review in a pedagogical manner some of the efforts aiming to extend the
gauge/gravity correspondence to non-conformal supersymmetric gauge theories in
four dimensions. After giving a general overview, we discuss in detail two
specific examples: fractional D-branes on orbifolds and D-branes wrapped on
supersymmetric cycles of Calabi-Yau spaces. We explore in particular which
gauge theory information can be extracted from the corresponding supergravity
solutions, and what the remaining open problems are. We also briefly explain
the connection between these and other approaches, such as fractional branes on
conifolds, branes suspended between branes, M5-branes on Riemann surfaces and
M-theory on G2-holonomy manifolds, and discuss the role played by geometric
transitions in all that.
