  The theory of Poisson-$\sigma$-models employs the mathematical notion of
Poisson manifolds to formulate and analyze a large class of topological and
almost topological two dimensional field theories. As special examples this
class of field theories includes pure Yang-Mills and gravity theories, and, to
some extent, the G/G gauged WZW-model. The aim of this contribution is to give
a pedagogical introduction, explaining many aspects of the general theory by
illustrative examples.
