In the second volume of the collection of works of the outstanding Russian scientist, academician V. A. Kotelnikov (1908-2005), prepared for the 100th anniversary of the scientist, included his work, which marked the beginning of new scientific areas in space exploration - space radiophysics and planetary radar. The results of these studies are extremely important in the study of the solar system and determined the further development of all space programs. In addition, the Appendix to this volume includes the latest unfinished work B. A. Koteln Ikova, drafts of which were published in 2008, after the departure of Vladimir Alexandrovich from life The expert opinion on this work . is also published. For scientists, specialists, students, as well as for anyone who is interested in the history of development and achievements of domestic science in the field of space exploration and radio astronomy