Columbia subject headings:
Civilization, Modern--20th century.
Germany--Intellectual life--20th century.
Learning and scholarship--History--20th century.
Physics--Philosophy.
Harvard subject headings:
Civilization, Modern--20th century
Germany--Intellectual life--20th century.
Learning and scholarship--History--20th century.
Physics--Philosophy
Princeton subject headings:
Civilization, Modern--20th century.
World politics--20th century.