Columbia subject headings:
Intelligence officers--Great Britain--Biography.
Intelligence service--Great Britain--History--20th century.
Knight, Maxwell, 1900-1968.
Harvard subject headings:
Intelligence officers--Great Britain--Biography.
Intelligence service--Great Britain--History--20th century.
Knight, Maxwell, 1900-1968.
Princeton subject headings:
Intelligence officers--Great Britain--Biography.
Intelligence service--Great Britain--History--20th century.
Knight, Maxwell, 1900-1968.