Starting from a relativistic many-baryon/lepton lagrangian density — in which charged baryons (i.e. p, n, Σ ±,0, Λ, Ξ 0,−, Δ ++,+0,−) interact via the exchange of scalar-, vector-, and isovector mesons (i.e., σ, ω, π, ρ), respectively — both the baryon composition and gross structural parameters of neutron stars (like radius, gravitational mass, moment of inertia, red shift) are calculated. The constraint of charge neutrality of neutron star matter, which demands for the incorporation of leptons (i.e., e −, μ −) into the theory, has been explicitly taken into account. The equation of state, which serves as an input for solving the Oppenheimer- Volkoff equation of stellar structure, is calculated for the Hartree as well as the Hartree-Fock approximation. Special emphasis is put towards comparing the outcome for both of these approximations. For example, we found for the maximum stable neutron star mass M/ M⊙ = 1.98 for the Hartree approximation and values of 2.18 and 2.31 for the Hartree-Fock treatments, respectively. Furthermore, the baryon compositions calculated for both of these approaches differ considerably from each other. Specifically, the Hartree-Fock approximation may not be suitable for the inclusion of the phenomenon of pion condensation in hadronic matter. The mathematical treatment of the many-baryon/lepton field theory is based on the Green function technique, as developed in some foregoing investigations for hot and dense matter.