Parton-hadron duality: Resonances and higher twists

We explore the physics of parton-hadron duality in the nucleon structure functions measured in lepton-nucleon scattering. We stress that duality allows one to extract the higher-twist matrix elements from data in the resonance region, or conversely to learn about the properties of resonances if the matrix elements are known. As an example, we construct the moments of ${\mathit{F}}_2$(x,${\mathit{Q}}^2$) for the low and medium ${\mathit{Q}}^2$ region, and from which we study the interplay between higher twists and the resonance contributions.