  We propose a self-contained description of Vasiliev higher-spin theories with
the emphasis on nonlinear equations. The main sections are supplemented with
some additional material, including introduction to gravity as a gauge theory;
the review of the Fronsdal formulation of free higher-spin fields; Young
diagrams and tensors as well as sections with advanced topics. The shortest
route to Vasiliev equations covers 40 pages.
  The general discussion is dimension independent, while the essence of the
Vasiliev formulation is discussed on the base of the four-dimensional
higher-spin theory. Three-dimensional and $d$-dimensional higher-spin theories
follow the same logic.
