Quark degrees of freedom in hadronic systems

Quantum Chromodynamics (QCD) is the theory of the strong interactions. We r eview descriptions of hadronic systems motivated by QCD, analyzing the rece nt controversy between gluonic and bosonic degrees of freedom under the pri sm of the Cheshire Cat Principle. Our analysis leads to an optimal scheme t o study hadronic properties. We proceed to extend this low energy descripti on to the deep inelastic regime.