THE STRUCTURE OF THE PROTON FROM POLARIZED PROTON-PROTON COLLISIONS

The Relativistic Heavy Ion Collider (RHIC)at Brookhaven
National Laboratory is the only polarized proton
collider in the world.  Experiments using both
transverse and longitudinal spin are now shedding
new light on the structure of the proton, especially
the gluon content and possible signatures of orbital
angular momentum.  Combined with Deep Inelastic
Scattering results, a clearer picture of the parton
model's successes and limitations is emerging.  I
will present recent and planned experimental results
with emphasis on those from the STAR experiment at RHIC.