The ever-quotable Mark Twain (No. 47 in a series)

The Mark Twain House and Museum in Hartford, Conn., has described the writer, humorist, entrepreneur, publisher and lecturer as "the quintessential American author." Others have praised Twain (real name: Samuel Langhorne Clemens) as "the father of American literature" and "the greatest humorist the United States has produced." Although Twain died more than a century ago, his wit and wisdom remain the stuff of legend.

"When I was a boy of fourteen, my father was so ignorant I could hardly stand to have the old man around. But when I got to be twenty-one, I was astonished at how much he had learned in seven years."