The question after the individual parton (quarks and gluons) contributions
to the spin of the nucleon is even after 20 years of experimental efforts
not yet solved.
After several very precise measurements in polarized deep inelastic
scattering it is clear, that the spin of the nucleon can not be explained
by the contribution of the quarks alone. This is affirmed by the newest
results from COMPASS, HERMES and JLAB on the inclusive spin structure
function g1 and on the individual contributions from the different quark
flavors from semi-inclusive deep inelastic scattering data.
Recently COMPASS and HERMES have started to measure the gluon polarization
by isolating the photon gluon fusion process in semi-inclusive deep
inelastic scattering; latest results on the contribution of the gluons to
the nucleon spin from these measurements and RHIC will be discussed.
The clear experimental evidence of exclusive reactions, especially DVCS,
allows in the formalism of generalised parton distributions the study of
an other component of the nucleon spin the orbital angular momentum.
The most recent results on indications of the size of the orbital angular
momentum of quarks will be presented.