Structure functions from deep inelastic lepton scattering

Abstract The current status of the nucleon structure functions as measured in charged lepton scattering is reviewed including the analysis of scale breaking and higher twists. Results of a new measurement of the ratio and the difference of the neutron and proton structure function are presented. The Gottfried sumrule appears to be broken indicating that d is more abundant than u in the proton. The status of the nuclear effects on structure functions is presented as measured in lepton scattering and Drell-Yan process on nuclear targets. The crucial question of whether nuclear effects break factorisation is investigated on the basis of currently available data.