Columbia subject headings:
Twain, Mark, 1835-1910.
Harvard subject headings:
Authors, American--19th century--Biography
Howells, William Dean, 1837-1920--Friends and associates.
Twain, Mark, 1835-1910
Twain, Mark, 1835-1910--Anecdotes.
Twain, Mark, 1835-1910--Criticism and interpretation.
Princeton subject headings:
Authors, American--19th century--Biography.
Twain, Mark, 1835-1910.