The properties of systems consisting of classical atoms with a short-range interaction and the processes occurring in them are studied. An asymptotic theory is presented for the transport coefficients and other parameters of a gas, which exploits the steepness of the interaction potential of the atoms in the repulsive region. A comparison of the parameters of various condensed inert gases shows that these parameters can be expressed in terms of the interaction potential between two atoms. On the basis of a model of close-packing of the atoms analyses are made of the properties of large clusters, the surface energy of condensed and porous systems, the surface tension of liquids and liquid metals, and of the solid-liquid phase transition.