  We briefly review results on nonlinear kinetic equation of Boltzmann type
which describe the evolution of wealth in a simple agents market. The
mathematical structure of the underlying kinetic equations allows to use
well-known techniques of wide use in kinetic theory of rarefied gases to obtain
information on the process of relaxation to a stationary profile, as well as to
identify simple interaction rules which are responsible of the formation of
Pareto tails.
