This uncommon short work, published in Esperanto in 1937 in Paris, describes racial distinctions, such as physical appearance and moral standards of different races. The author also gives theories on interracial mixing, and discusses the current situation of Jews in Germany. The author Paul de Neergaard with this work opposed racism. The book was printed two years before the beginning of WWII.
The author Paul de Neergaard (1907-1987) was a Danish esperantist and agronomist, also known as the father of seed pathology. He was a member of Academy for Esperanto, and a professor in Beirut and Mysore.
References: Ulrich Lins, Dangerous Language — Esperanto under Hitler and Stalin 2017, p. 136.