In The Heroic Earth, David T. Murphy argues that geopolitical ideas were most dynamic and significant in Germany not during the Nazi era (1933-45) but in the democratic culture of the Weimar Republic (1919-33). By helping to condition the German population to geopolitical ideas, which emphasized revision of the Versailles settlement and enlarging Germany's living space, geopolitics helped contribute to Nazi imperialism. Theories of geographical determinism shaped German thinking about politics, race, science, education, aesthetics, and many other subjects on the eve of the Nazi era. Challenging traditional historiography, Murphy argues that geopolitics faded in importance after Adolf Hitler came to power.