1. Calculations of the behavior of materials under impulsive loads are based on fundamental equations of state. These equations link loading and deformation processes with the critical conditions of the fracture of local regions of the material. 2. Dynamic tests of specimens may be recommended for obtaining experimental data that will make it possible to construct the fundamental equations of state with an allowance for the strain rate and loading history. Here, reliable results can be obtained under conditions of high-rate loading only in tests conducted at a constant strain rate. 3. There are very few experimental studies of the behavior of materials with high-rate deformation under conditions of a complex stress state as well as studies of complex loading conditions and loading paths in a stress (strain) space. This makes the development of appropriate experimental methods and the conducting of pertinent studies more urgent. 4. It is necessary to develop experimental methods to investigate the laws of crack initiation and growth in a material in the propagation of intensive loading waves and to determine dynamic criteria of the local fracture of materials.