In this and a companion paper, Larry McLerran and Raju Venugopalan proposed a classical model for the scattering of large nuclei at high energies. They argued that the color charges of the valence quarks can be treated as static sources which propagate along the light cone. A high density of soft gluons is generated, and can be described as a classical gauge field. This provides an energy scale much larger than the usual QCD scale, and so a small QCD coupling. Fluctuations in the color charge are treated as Gaussian random variables, and give the quark and gluon distribution functions to lowest order in the coupling. The McLerran-Venugopalan model is the starting point of an effective theory known as the color glass condensate (CGC), which describes the initial state of heavy ion collisions at high energies.