Columbia subject headings:
Harvard subject headings:
Authors, American--19th century--Biography
Novelists, American--19th century--Biography
Twain, Mark, 1835-1910
Twain, Mark, 1835-1910--Knowledge--United States.
United States--Civilization--19th century.
Princeton subject headings:
Novelists, American--19th century--Biography.
Twain, Mark, 1835-1910--Contemporary America.
Twain, Mark, 1835-1910.
United States--Civilization--19th century.