Translating Quark Dynamics into Hadron Physics (and back again)

Why should we study mesons in 2002? Two approaches to relating quark and gluon dynamics to hadron physics, namely QCD sum rules and effective field theories, are briefly discussed. These are linked by progress in the study of strong QCD, both by lattice Monte Carlo methods and in the continuum. These provide the translation from quark dynamics to hadron physics and back again. Scope for more theoretical work and further experiments to elucidate the nature of the QCD vacuum and its precise relation to scalar mesons and their interactions is outlined.