6th Edition . , dop. - M. : Science. Gl. Red. phys. -mat. lit. , 1987 - 320 s. (Problems of Science and Technology .) progress). Part Three . Reasonable Life in the Universe . General remarks . Development of the Solar System by mankind . Radio communication between civilizations on different planetary systems. The possibility of interstellar communication by optical methods. Communication with alien civilizations by means of automatic probes. Theoretical and Probabilistic Analysis of Interstellar Radio Communication . Nature of Signals . On the possibility of direct contacts between alien civilizations . Comments on the pace and nature of technological development of mankind . Intelligent Life as a Space Factor . Where are you, brothers in mind? Annex i. The Search for Extraterrestrial Civilizations . Application iI. Is it possible to connect with intelligent beings of other planets?Are there other planetary systems?The collapse of the Jeans hypothesis. What does the rotation of the stars say . Multiple planetary systems. How many planets can be the cradle of intelligent beings? What is the nature of this communication channel?How far will the signal come?How to overcome interference?In which direction to search?Appendix III. Are There Extraterrestrial Civilizations?