This report presents the latest results on structure functions, as available at the Lepton-Photon Symposium 1999. It focuses on three experimental areas: new structure function measurements, in particular from HERA at low x and high Q2; results on light and heavy flavor densities; and determinations of the gluon distribution and of αs. As the talk was delivered at a historic moment and place, a few remarks were added recalling the exciting past and looking into the promising future of deep inelastic scattering (DIS).
Deep inelastic scattering at low x: generalized vector dominance and the color dipole picture