  We examine the present status of the Bjorken sum rule in the light of recent
data on the spin structure functions of the proton, neutron and deuteron
obtained by the CERN and SLAC experimental groups. We also discuss the role of
possible higher-twist contributions and higher-order PQCD corrections and
comment on the extraction of the necessary parameters, D and F, obtained from
hyperon semi-leptonic decays.
