The starting point of his analysis is the "struggle for daily bread" (food production) as the basis of human society. From this need for self-preservation, he develops his central idea of the relationship between the population and the size of the habitat of a people. If the habitat cannot provide sufficient resources for survival, degeneration and a decline of the nation results. Hitler raises the struggle for adequate habitat to a central principle of human history. Hitler points out that this battle is often enforced militarily, as history has adequately demonstrated.