For many decades the conventional quark anti-quark model of mesons has provided a satisfactory description of the experimentally observed spectrum. In recent years, strong experimental evidence of meson states that cannot be formed by a quark anti-quark pair has emerged. At the same time, recent first-principles calculations of the meson spectrum from quantum chromodynamics (QCD) have suggested the presence of unconventional meson states. However, the correspondence between newly-discovered unconventional states and predicted states is not immediately apparent. In this talk I'll motivate using meson spectroscopy as a tool for studying QCD, discuss a selection of recent experimental results, and future prospects for studying the meson spectrum.

Argonne Physics Division Colloquium Schedule