Mark Twain was an American author and humorist, born in 1835. He is best known for his novels The Adventures of Tom Sawyer and Adventures of Huckleberry Finn, which are considered classics of American literature. He was also a riverboat pilot, journalist, lecturer, and entrepreneur. His real name was Samuel Langhorne Clemens, but he adopted the pen name MARK Twain, which was derived from the call used by Mississippi River boatmen to indicate two fathoms of water.