  I discuss how global QCD fits of parton distribution functions can make the
somewhat separated fields of high-energy particle physics and lower energy
hadronic and nuclear physics interact to the benefit of both. I review specific
examples of this interplay from recent works of the CTEQ-Jefferson Lab
collaboration, including hadron structure at large parton momentum and gauge
boson production at colliders. I devote particular attention to quantifying
theoretical uncertainties arising in the treatment of large partonic momentum
contributions to deep inelastic scattering observables, and to discussing the
experimental progress needed to reduce these.
