A review is given of the results of experimental studies of interactions between high-energy particles ( $E_0\gtrsim$ 20 GeV) and nuclei. It is emphasized that experiment shows a very weak dependence of many of the important parameters of multiple production on the number of nucleons in the nucleus. Observed phenomena can be understood either within the framework of the hydrodynamic (classical) approach or within the framework of the quantum-mechanical, field-theoretical approach (parton model). Suggestions are outlined for further studies that might throw light on the mechanism of space-time development of the interaction processes. The references cover the period up to May 1, 1976.