This book highlights the capabilities and limitations of radar and air navigation. It discusses issues related to the physical principles of an electromagnetic field, the structure of radar information, and ways to transmit it. Attention is paid to the classification of radio waves used for transmitting radar information, as well as to the physical description of their propagation media. The third part of the book addresses issues related to the current state of navigation systems used in civil aviation and the prospects for their development in the future, as well as the history of satellite radio navigation systems.  The book may be useful for schoolchildren, interested in the problems of radar and air navigation.