CONTENTS[br] 1. Introduction 551[br] 2. Theoretical models of the semiconductor-metal transition in disordered systems 552[br] 3. Semiconductor-metal transition in molten semiconductors at high temperatures 561[br] 4. Semiconductor-metal transition and criterion for minimal metallic conductivity of melts at [i]T[/i]>[i]T[/i][sub]mp[/sub] 564[br] 5. Metal-semiconductor transition near critical points of metals and semiconductors 565[br] A. Results of experimental investigations of cesium and mercury 565[br] 1) Liquid metal range 567[br] 2) Transition range 567[br] 3) Range with some properties of liquid semiconductors 568[br] 4) Range of dense ionized gases 569[br] B. Results of experimental investigations of selenium and arsenic. Se–Te system 570[br] 1) Selenium and arsenic 570[br] 2) Se–Te system 571[br] 6. Conclusions 571[br] References 572[br]