  I discuss a number of novel topics in QCD, including the use of the AdS/CFT
correspondence between Anti-de Sitter space and conformal gauge theories to
obtain an analytically tractable approximation to QCD in the regime where the
QCD coupling is large and constant. In particular, there is an exact
correspondence between the fifth-dimension coordinate z of AdS space and a
specific impact variable zeta which measures the separation of the quark
constituents within the hadron in ordinary space-time. This connection allows
one to compute the analytic form of the frame-independent light-front
wavefunctions of mesons and baryons, the fundamental entities which encode
hadron properties and allow the computation of exclusive scattering amplitudes.
I also discuss a number of novel phenomenological features of QCD. Initial- and
final-state interactions from gluon-exchange, normally neglected in the parton
model, have a profound effect in QCD hard-scattering reactions, leading to
leading-twist single-spin asymmetries, diffractive deep inelastic scattering,
diffractive hard hadronic reactions, the breakdown of the Lam Tung relation in
Drell-Yan reactions, and nuclear shadowing and non-universal
antishadowing--leading-twist physics not incorporated in the light-front
wavefunctions of the target computed in isolation. I also discuss tests of
hidden color in nuclear wavefunctions, the use of diffraction to materialize
the Fock states of a hadronic projectile and test QCD color transparency, and
anomalous heavy quark effects. The presence of direct higher-twist processes
where a proton is produced in the hard subprocess can explain the large
proton-to-pion ratio seen in high-centrality heavy-ion collisions.
