Columbia subject headings:
Civilization--Philosophy.
History--Philosophy.
Philosophers--Germany.
Spengler, Oswald, 1880-1936.
Harvard subject headings:
Philosophy, European--20th century.
Spengler, Oswald, 1880-1936.
Princeton subject headings:
Philosophy, European--20th century.
Spengler, Oswald, 1880-1936.