This paper presents a method for computing quark and gluon distribution functions in very large nuclei at small Bjorken x. The authors argue that for sufficiently large nuclei, the density of quarks and gluons per unit area per unit rapidity is large enough that weak coupling methods can be used. They show that the computation of these distribution functions can be recast as a many-body problem with a modified propagator, a coupling constant that depends on the multiplicity of particles per unit rapidity per unit area, and for non-abelian gauge theories, some extra media-dependent vertices. They explicitly compute the gluon distribution function to lowest order and argue how they may be computed in higher order. The authors also argue that the quark distribution functions are computable in this kinematic region and outline how to do the lowest order computation. They show that the power dependence of the distribution functions in Bjorken x may be modified in higher orders of perturbation theory. The paper also discusses the implications of these results for the infrared structure of the theory and the relationship between the distribution functions and deep inelastic scattering. The authors conclude that the computation of quark and gluon distribution functions in very large nuclei is a promising approach for understanding the behavior of these particles in high-energy collisions.This paper presents a method for computing quark and gluon distribution functions in very large nuclei at small Bjorken x. The authors argue that for sufficiently large nuclei, the density of quarks and gluons per unit area per unit rapidity is large enough that weak coupling methods can be used. They show that the computation of these distribution functions can be recast as a many-body problem with a modified propagator, a coupling constant that depends on the multiplicity of particles per unit rapidity per unit area, and for non-abelian gauge theories, some extra media-dependent vertices. They explicitly compute the gluon distribution function to lowest order and argue how they may be computed in higher order. The authors also argue that the quark distribution functions are computable in this kinematic region and outline how to do the lowest order computation. They show that the power dependence of the distribution functions in Bjorken x may be modified in higher orders of perturbation theory. The paper also discusses the implications of these results for the infrared structure of the theory and the relationship between the distribution functions and deep inelastic scattering. The authors conclude that the computation of quark and gluon distribution functions in very large nuclei is a promising approach for understanding the behavior of these particles in high-energy collisions.