He was born November 30, 1835, Florida, Missouri, U.S.—died April 21, 1910, Redding, Connecticut). He was a humorist, journalist, lecturer, and novelist.
Samuel Langhorne Clemens, had his writing name due to his great humor and was in need of a pen name for his writings; earlier he had occasionally worked the river boats on the Mississippi in his early twenties and he chose that of Mark Twain.
‘Twain’ means the safe depth of the river for paddle wheel riverboat for travel, in this case-it was two fathoms, which is 12 feet. When the safe depth was achieved, the boat deckhand would continuously throw a rope over the side and yell out “Mark” and the depth when it was navigably safe, this being two fathoms. As the paddle wheel traveled the river, it was necessary to be critically aware of the depth of the water at all times, so the paddle wheel boat would not be grounded on the sandbars.
Later, Samuel Clemens became a writer and the basis of his imagination was that of a town by the name of Hannibal, always in mind of the events taking place upon the arrival and excitement to see the arriving or departing gamblers, stevedores, and pilots, the raftsmen and elegant travelers, all bound for somewhere surely glamorous and exciting, would have impressed a young boy and stimulated his already active imagination. Here, too, were local diversions as well—fishing, picnicking, and swimming. A boy might swim or canoe to and explore Glasscock’s Island in the middle of the Mississippi River, or he might visit the labyrinthine McDowell’s Cave, about 2 miles south of town. The first site evidently became Jackson’s Island in Adventures of Huckleberry Finn; the second became McDougal’s Cave in The Adventures of Tom Sawyer.
On Ideas "The man with a new idea is a crank until the idea succeeds." Mark Twain