This document provides biographical information about German geographer Friedrich Ratzel and summarizes his key geographic works and contributions. It discusses how Ratzel introduced concepts like Lebensraum and viewed states as organic entities seeking to expand their territory. While he did not advocate aggressive expansion, his ideas were later interpreted and built upon by others to justify German imperialism leading up to World War II. The document also summarizes Ratzel's major works, including Anthropogeographie and Politische Geographie, and how they established foundations for human and political geography.