Columbia subject headings:
Authors, English--20th century--Biography.
Authors, German--20th century--Biography.
Koestler, Arthur, 1905-1983.
Koestler, Cynthia, 1928-1983.
Harvard subject headings:
Authors, English--20th century--Biography
Authors, German--20th century--Biography
Koestler, Arthur, 1905-1983--Biography.
Koestler, Cynthia, 1928-1983.
Princeton subject headings:
Authors, English--20th century--Biography.
Koestler, Arthur, 1905---Biography.
Koestler, Cynthia, 1928-1983.