19th century illustration of Mark Twain (1835-1910), US author and novelist, standing on stage and giving a speech to an audience. Mark Twain was the pen-name of Samuel Langhorne Clemens. His most famous novels include 'The Adventures of Tom Sawyer' (1876), 'Adventures of Huckleberry Finn' (1885), and 'A Connecticut Yankee in King Arthur's Court' (1889). Twain, an inventor and friend of the physicist Nikola Tesla, took a great interest in science and technology. Twain was also much sought after as a featured speaker. His autobiography was published 100 years after his death, and became a best-seller.