  I review some central physics opportunities at the 15 ... 30 GeV continuous
beam electron accelerator ELFE, proposed to be built in conjunction with the
DESY linear collider. Our present detailed knowledge of single parton
distributions in hadrons and nuclei needs to be supplemented by measurements of
compact valence quark configurations, accessible through hard exclusive
scattering, and of compact multiparton subsystems which contribute to
semi-inclusive processes. Cumulative (x>1, x_F>1) processes in nuclei measure
short-range correlations between partons belonging to different nucleons in the
same nucleus. The same configurations may give rise to subthreshold production
of light hadrons and charm.
