  These notes aim at providing a pedagogical and pedestrian introduction to the
subject and assume no previous knowledge apart from that of general relativity.
We shall first recall the "frame" formulation of the later theory, then
particularize it to three dimensions, and will end those preliminaries by
reviewing the formulation of three-dimensional gravity as a gauge theory
governed by a Chern-Simons action. An analogous path is then followed for
higher-spin fields at the free level. Once the equivalent Chern-Simons action
is established thereof, it is then explained how one can formulate
three-dimensional higher-spin theories at the non-linear level by considering
higher-spin Lie algebras. We then move on to commenting on what has already
been done in the context of these theories and what interesting areas of
research are currently under investigation.
