  Recent progress in the field of spin physics of high energy particle
interactions is reviewed with particular emphasis on the spin structure
functions as measured in polarized deep inelastic lepton-nucleon scattering
(DIS). New measurements are presented to obtain more direct information on the
composition of the nucleon angular momentum, with results from semi-inclusive
DIS accessing flavour-separated parton distribution functions (PDF) and with
first data from hard exclusive reactions which may be interpreted in terms of
recently developed generalizations of parton distribution functions (GPD).
Finally, experimental prospects are outlined which will lead to a further
development of the virtues of QCD phenomenology of the spin structure of the
nucleon.
