The encyclopedia invites the reader to the land of practical electronics. The main goal of the book is to interest readers of different ages in radio electronics and computer technology, as well as to help in mastering the basics of electronics in both its theoretical and practical aspects. The book contains many useful, in practical terms, radio-electronic circuits, equipped with a full description of the technology for their manufacture, which can be made independently by a beginning radio amateur. The reference materials in the book on various areas of radio electronics, as well as a dictionary of radio electronics terms, are intended to be of great benefit in practical amateur radio design. The book is intended for a wide range of readers interested in practical radio electronics. It can be useful for both schoolchildren choosing a career path, and students of technical universities specializing in this field of knowledge, as well as business people who want to invest and increase their capital in the field of radio broadcasting.