  There have been many demonstrations of the utility of the Dyson-Schwinger
equations of QCD as a systematic, phenomenological framework for describing the
perturbative and non-perturbative dynamics of hadrons in terms of Euclidean
Green functions of quarks and gluons. Still, there remain some unanswered
questions regarding the theoretical underpinnings of the approach. I review
several studies that are shedding light on how these questions might be
resolved and review predictions for some exotic meson states.
