The book concerns the dynamic response of materials due to intensive impulsive loadings. The materials considered are primarily solids, although most of the discussions are also applicable to fluids. The loading and response in general happen within a very short time, in the order of microseconds, rather than milliseconds. The duration of the loading, whether mechanical impact or thermodynamic energy input, may sometimes be described in terms of nanoseconds. The magnitude of the loading is such that the initial stress in the material is high, and subsequently decays to moderate values, so that both compressibility and strength effects are important. The book is concerned only with material response, and not with structural response.