  In an ungauged supergravity theory, the presence of a \emph{scalar potential}
is allowed only for the minimal $\N=1$ case. In extended supergravities, a
non-trivial scalar potential can be introduced without explicitly breaking
supersymmetry only through the so-called \emph{gauging procedure}. The latter
consists in promoting a suitable global symmetry group to local symmetry to be
gauged by the vector fields of the theory. Gauged supergravities provide a
valuable approach to the study of superstring flux-compactifications and the
construction of phenomenologically viable, string-inspired models. The aim of
these lectures is to give a pedagogical introduction to the subject of gauged
supergravities, covering just selected issues and discussing some of their
applications.
