  Exclusive meson leptoproduction from nucleons in the deeply virtual exchanged
boson limit can be described by generalized parton distributions (GPDs).
Including spin dependence in the description requires 8 independent
quark-parton and gluon-parton functions. The chiral even subset of 4
quark-nucleon GPDs are related to nucleon form factors and to parton
distribution functions. The chiral odd set of 4 quark-nucleon GPDs are related
to transversity, the tensor charge, and other quantities related to
transversity. Different meson or photon production processes access different
combinations of GPDs. This is analyzed in terms of t-channel exchange quantum
numbers, $J^{PC}$ and it is shown that pseudoscalar production can isolate
chiral odd GPDs. There is a sensitive dependence in various cross sections and
asymmetries on the tensor charge of the nucleon and other transversity
parameters. We also consider, briefly, the analyticity of the GPDs and the
problems with the partonic interpretation in the ERBL region.
