Columbia subject headings:
Liberty--History--19th century.
Marx, Karl, 1818-1883.
Reason--History--19th century.
Harvard subject headings:
Liberty--History--19th century.
Marx, Karl, 1818-1883
Reason--History--19th century.
Princeton subject headings:
Liberty--History--19th century.
Marx, Karl, 1818-1883.
Reason--History--19th century.