Leading Nazis, and early 1900 influential German biologists, revealed in their writings that Darwin’s theory and publications had a major influence upon Nazi race policies. Hitler believed that the human gene pool could be improved by using selective breeding similar to how farmers breed superior cattle strains. In the formulation of their racial policies, Hitler’s government relied heavily upon Darwinism, especially the elaborations by Spencer and Haeckel. As a result, a central policy of Hitler’s administration was the development and implementation of policies designed to protect the superior race’. This required at the very least preventing the inferior races’ from mixing with those judged superior, in order to reduce contamination of the latter’s gene pool. The superior race’ belief was based on the theory of group inequality within each species, a major presumption and requirement of Darwin’s original survival of the fittest’ theory. This philosophy culminated in the final solution’, the extermination of approximately six million Jews and four million other people who belonged to what German scientists judged as inferior races’.