This rare book up till now could only be found from sellers abroad. It has a detailed biography of the German Chessmaster, Diemer who was the cofounder and main proponent of the Blackmar-Diemer gambit. Diemer was a controversial figure because of his Nazi political views and psychological problems. The gambit, 1. d4 d5 2. e4!? is very popular among players with ELO less than 2000, and for good reason, as it often leads to quick and flashy victories. In the United States, chessmasters like Peter Webster and Chuck Diebert have made it their main weapon as white so it is not just for class players. 56 annotated games are included after a 230 page biography. 280 pages in German language, easy to read with the Google translate app. The author Georg Studier is a German chess master who also played the gambit. Chess.com has a good article on Diemer: https://www.chess.com/blog/ThePawnSlayer/the-life-and-games-of-emil-josef-diemer-the-madman-of-chess-part-1