Columbia subject headings:
Illustration of books--United States--19th century.
Twain, Mark, 1835-1910--Illustrations.
Harvard subject headings:
Illustration of books--19th century--United States.
Twain, Mark, 1835-1910--Illustrations.
Princeton subject headings:
Illustrators--United States.
Twain, Mark, 1835-1910--Illustrations.