Verlag Walter de Gruyter, Berlin, 1926, in German language, original linen binding, format 11.5 x 17 cm, viii+62 pages, 150 grams, with a chess board and chess pieces. Condition: good.   * The cardboard chess game is integrated into the inside of the back cover. The envelope with the chess pieces is closed, the notches are intact, 99 years after the publication of this booklet. The chessboard looks unused. (see 2nd photo).

The booklet is based on lectures given by the author at the Berlin radio station and later at the German tadio station Deutsche Welle 1300.