  We present the status of our formalism for extracting three-particle
scattering observables from lattice QCD (LQCD). The method relies on relating
the discrete finite-volume spectrum of a quantum field theory with its
scattering amplitudes. As the finite-volume spectrum can be directly determined
in LQCD, this provides a method for determining scattering observables, and
associated resonance properties, from the underlying theory. In a pair of
papers published over the last two years, two of us have extended this approach
to apply to relativistic three-particle scattering states. In this talk we
summarize recent progress in checking and further extending this result. We
describe an extension of the formalism to include systems in which two-to-three
transitions can occur. We then present a check of the previously published
formalism, in which we reproduce the known finite-volume energy shift of a
three-particle bound state.
