First published as a series in The South African Observer from 1958 to 1959, The Importance of Racial Integrity was philosopher Anthony M. Ludovici's most important writing on race, racial differences and the necessity to avoid racial mixing in order to preserve unique cultures and the identity of all the peoples of the world. He spells out what race is, how races are defined and then moves on to a detailed discussion of the effects of racial mixing upon the physical, mental and civilizational levels of society. "We have but to glance at the representatives of some of the world's most distinct races of Man in order at once to see that, unless there can be no relation whatsoever between appearance and character - i.e., between physical and psychological traits - it is impossible to the point of absurdity to speak of their equality. For even if for the moment we leave aside the question whether there are superior and inferior races, we have but to contemplate the sharp bodily disparities between the best-known races of Man in order at once to infer that these physical differences must be accompanied by differences in mental powers, character, ability, temperament and tastes." Eugenics and Consanguineous Marriages is an essay first published in The Eugenics Review in 1933, based on a lecture Ludovici presented to the Eugenics Society. In this essay, he discusses the effects of consanguineous interbreeding upon stocks of animals-and humans.