To cite this article: Stanisł Aw Kryszewski (1993) On the van der Waals interaction between an atom and a dielectric medium, Molecular Physics, 78:5, 1225-1246,The energy of the van der Waals interaction between a neutral atom and a dielectric medium is rederived. The new method of derivation uses only linear response theory and the concepts of the classical eleetrodynamics. It is shown that there is no need to invoke quantum electrodynamic ideas. The presented approach is aimed at providing the easy-to-use expressions necessary to interpret recent experiments. The derived expression for the energy of the van der Waals interaction is valid for any retardation times, viz., for any distances between an atom and the dielectric which are large compared with the characteristic dimensions or the crystalline lattice of the dielectric medium. Several limiting cases, such as for negligible and large retardation, are considered. The connection with intermolecular potentials is also established. Finally, explicit expressions for the van der Waals energy are given for some specific analytical models of the atomic polarizability and the dielectric constant of the medium considered.