The assumption of a neutral-atom reference state for the study of crystalline solids yields a first-order approximation to the cohesive energy that is related to the classical electrostatic overlap energy of independent atomic charge distributions. This independent-atom model (IAM) energy provides approximately correct binding energies for crystalline solids generally. The IAM energies provide estimates to cohesive energies that compare favourably with the Madelung (point charge) energies for a wide range of solids. Exchange, charge-transfer and polarisation terms may be viewed as higher-order corrections to the IAM term. IAM energies make a significant contribution to the binding energies even for the rare-gas solids. IAM energies provide better estimates for the alkali halide lattices than do the Madelung energies.