Spin Structure of the Nucleon

HERMES is a second generation experiment to study the spin structure of the nucleon, in which measurements of the spin dependent properties of semi-inclusive deep-inelastic lepton scattering are emphasized. The first experimental results from measurements of single-spin asymmetries for pions and kaons in deep-inelastic scattering with transverse target polarization are discussed. Longitudinally polarized beam and target data provide information on the flavor decomposition of the polarized quark distributions in the nucleon and a first glimpse of the gluon polarization. Moreover, first preliminary results for the unpolarized ep → enπ+ total cross section are presented and compared to Generalized Parton Distribution calculations.