  We discuss the transformation of the QCD temporal-gauge Hamiltonian to a
representation in which it can be expressed as a functional of gauge-invariant
quark and gluon fields. We show how this objective can be realized by
implementing the non-Abelian Gauss's law, and by using the mathematical
apparatus developed for that purpose to also construct gauge-invariant quark
and gluon fields. We demonstrate that, in the transformed QCD Hamiltonian, the
interactions of pure-gauge components of the gauge field with color-current
densities are replaced by nonlocal interactions connecting quark color-charge
densities to each other and to `glue'-color. We discuss the nonperturbative
evaluation of these nonlocal interactions, which are non-Abelian analogs of the
Coulomb interaction in QED, and we explore their implications for QCD in the
low-energy regime.
