The presently-known elastic and thermal expansion properties of explosive single crystals are summarized. Through the classical averaging methods of Voigt-Reuss-Hill-Neerfeld, the single crystal elasticities are used to determine the macroscopic isotropic elastic constants. from which the corresponding sound velocities are also obtained, together with estimates of the Hugoniots. Qualitative and semi-quantitative approaches are suggested to be obtained from the single elastic properties, in addition, other aspects of technical importance, such as ductility, pressability of powders, prediction of the existence of polymorphs, thermal shock resistance, the Hugoniot elastic limit (HEL), aging and detonic properties can also be derived. By comparing the wave properties, the crude macroscopic approximation of detonation results, which never involves the fundamental properties in the mesoscaie. One goal for this work was to demonstrate a ranking between the elastic anisotropies and (shock) sensitivities of crystalline explosives. This ranking does not exist. Another goal was to provide a screening method for new explosives with a very limited amount of material.