  I review the constituent contributions to the spin of the proton extracted
from recent data at CERN, SLAC and DESY. The valence, sea quark and antiquark
spin-weighted distributions are determined separately. The data appear to imply
a small to moderate polarized gluon distribution, so that the anomaly term is
not significant in determining these contributions. We have analyzed the
consistency of the results obtained from various sets of data and the Bjorken
Sum Rule. All data are consistent with the sum rule, but they differ in the
contribution of the strange sea to proton spin. This and the remaining
uncertainty in the polarized gluon distribution pose unanswered questions about
hadronic spin. Further experiments are suggested which can extract information
about the polarized gluon and sea to address these questions.
