  We summarize recent developments in understanding the concept of generalized
parton distributions (GPDs), its relation to nucleon structure, and its
application to high-Q2 electroproduction processes. Following a brief review of
QCD factorization and transverse nucleon structure, we discuss (a) new
theoretical methods for the analysis of deeply-virtual Compton scattering
(t-channel-based GPD parametrizations, dispersion relations); (b) the
phenomenology of hard exclusive meson production (experimental tests of
dominance of small-size configurations, model-independent comparative studies);
(c) the role of GPDs in small-x physics and pp scattering (QCD dipole model,
central exclusive diffraction). We emphasize the usefulness of the transverse
spatial (or impact parameter) representation for both understanding the
reaction mechanism in hard exclusive processes and visualizing the physical
content of the GPDs.
