(German for "habitat" or literally "living space") served as a major motivation for Nazi Germany's territorial aggression. In his book Mein Kampf, Adolf Hitler detailed his belief that the German people needed Lebensraum (for a Grossdeutschland, land, and raw materials), and that it should be taken in the East. It was the stated policy of the Nazis to kill, deport, Germanize or enslave the Polish, and later also Russian and other Slavic populations, and to repopulate the land with reinrassig Germanic peoples. The entire urban population was to be exterminated by starvation, thus creating an agricultural surplus to feed Germany and allowing their replacement by a German upper class.