  I review the most important single- and double-spin asymmetries that allow
for the extraction of transversity and other chiral-odd and/or T-odd parton
densities, necessary to explore the partonic content and the spin structure of
the nucleon. With particular reference to the proposed GSI-HESR facility, I
report on some Monte-Carlo simulations of cross sections and spin asymmetries
for (un)polarized Drell-Yan with protons and antiprotons at the proposed
kinematics for this future facility.
