In the lattice QCD approach to hadron spectroscopy one can extract

finite-volume stationary-state energies, including excited states, from

temporal correlators.  Probe interpolating operators from correlators

which are estimated via Monte Carlo integration: these operators create

single- and two-hadron states with spatially displaced quarks, with an eye

towards possible tetraquark states.  Studies of dynamical quarks in SU(3)

gauge theory on large lattices with near-physical pion masses are made

possible by new techniques in operator smearing and stochastic estimation

of quark propagators.  Given the spectrum in finite-volume, the Luscher

method allows one to relate this to infinite-volume resonances; recent

results include the rho resonance in pion scattering, on a large 32^3 by

256 lattice at a heavy pion mass of 240 MeV.