With 127 explanatory drawings, principle diagrams, photographs of radio stations, transmitters, generators, etc. Berlin. Knowledge. 1922. 172 pp, c ill. Hardcover. Reduced format. Among the great discoveries and inventions of the late XIX and early XX centuries, radiotelegraphy undoubtedly belongs to one of the first places. Acquaintance with this new field of science and technology, quickly penetrating into the environment of everyday life, has become a necessity and need of all educated people. Acquaintance with radiotelegraphy is not only of special interest, it is captured and new highlights the deepest and most fascinating issues of a general nature. The book is written for lovers of knowledge, even if they have not passed a systematic course in physics and electrical engineering. Our task is not to teach radiotelegraphy, but, above all, to set forth, in a form that is as comprehensible as possible, its most important foundations and to acquaint the reader with the striking achievements and improvements of this work. But those who would like to work in the same direction further, having read this book, will no longer be “alien” in radiotelegraphy. They will only have to supplement with technical and practical information the general foundations given in this work. For teachers and amateurs, at the end of the book, instructions are given on how to arrange small demonstrative radio stations from improvised materials and a receiver for listening to powerful stations at short distances. The authors express their gratitude to Telefunken for the kindly provided photos.