  Many features of granular media can be modelled as a fluid of hard spheres
with {\em inelastic} collisions. Under rapid flow conditions, the macroscopic
behavior of grains can be described through hydrodynamic equations. At
low-density, a fundamental basis for the derivation of the hydrodynamic
equations and explicit expressions for the transport coefficients appearing in
them is provided by the Boltzmann kinetic theory conveniently modified to
account for inelastic binary collisions. The goal of this chapter is to give an
overview of the recent advances made for binary granular gases by using kinetic
theory tools. Some of the results presented here cover aspects such as
transport properties, energy nonequipartition, instabilities, segregation or
mixing, non-Newtonian behavior, .... In addition, comparison of the analytical
results with those obtained from Monte Carlo and molecular dynamics simulations
is also carried out, showing the reliability of kinetic theory to describe
granular flows even for strong dissipation.
