Columbia subject headings:
Twain, Mark, 1835-1910.
Harvard subject headings:
Authors, American--19th century--Biography
Biographies
Humor
Twain, Mark, 1835-1910--Journeys.
Twain, Mark, 1835-1910--Travel.
Princeton subject headings:
Authors, American--19th century--Biography.
Twain, Mark, 1835-1910--Travel.