Columbia subject headings:
Harvard subject headings:
France--Foreign relations--Great Britain.
Great Britain--Foreign relations--France.
Princeton subject headings:
Espionage, British--France--History--19th century.
France--Foreign relations--1789-1815.
France--History--Revolution, 1789-1799--Secret service.
Great Britain--History--1789-1820.
Napoleonic Wars, 1800-1815--Secret service.
Secret service--Great Britain.