This unusual book in Esperanto was published in Cologne a year before the Nazi Party banned the Esperanto language. The book was written by an Austrian Esperanto author Erich Kilian, who also designed the cover.
In 1935, a year after the book was published, Esperanto was forbidden in Germany by the Nazis, who considered it a language of the Bolsheviks and Jews. In Mein Kampf Adolf Hitler wrote the language could be used for an international Jewish conspiracy.
The publishing house Heroldo de Esperanto from Cologne, which issued that book, was publishing a magazine in Esperanto from 1920. The house was closed by the Nazi Party in 1936 and its presses were confiscated. It reopened after the war and continued publishing the magazine until 1961.
Only six examples of this book are known in the libraries worldwide.
References: OCLC 24709444; Historio de Esperanto, 1964.