The book discusses the use of frequency predistortion and correction in tape recorders necessary to compensate for losses arising in the recording and playback processes, and describes various types of these losses. Particular attention is paid to the optimal distribution of the total value of the losses to be compensated between the recording and reproducing channels and the method of standardizing the amplitude-frequency characteristics of these channels. The book is designed for trained radio amateurs and can be useful for specialists involved in the development and testing of tape recorders.