In this first English-language monograph about the Polish historian Feliks Koneczny (1862-1949), Andrew Kier Wise explains Koneczny's theories and the ongoing debate about their meaning and relevance for Poland in the twenty-first century. Koneczny believed in a "plurality of civilizations" rather than a universal path of historical development. Developed fully during the troubled interwar period, his "science of civilizations" prefigured the "clash of civilizations" theories of our own era. Koneczny was especially concerned with pressure from "the Orient" on Polish society by the so-called Byzantine, Turanian, and Jewish civilizations. He believed that Poland's distinct cultural identity was grounded in Latin (Western) civilization and derived from the classical heritage of the Roman Republic and medieval Catholicism. Adherents to Koneczny's worldview--which Wise defines as "Konecznian fundamentalism" or "civilizational fundamentalism"--embrace Koneczny's "quincunx of existential values" as a way to understand the world. Koneczny's theories and analytical framework thus provide a scholarly foundation for popular criticism of globalization, cosmopolitanism, immigration, feminism, the European Union, and other perceived threats to traditional Polish society.