  Lattice QCD already offers the possibility of extracting three-hadron
scattering quantities from first principles. In the last few years, significant
progress has been achieved in developing and applying the finite-volume
three-body formalism. The formalism is now able to treat physically relevant
systems of three mesons, including those with resonances, as well as three-body
decays. In this talk, I will review the state of the art, and comment on recent
applications to lattice QCD data for systems of three pions and kaons.
