Mark Twain Samuel Langhorne Clemens (November 30, 1835 - April 21, 1910), better known by his pen name Mark Twain, was an American humorist, novelist, writer, and lecturer. Although Twain was confounded by financial and business affairs, his humor and wit were keen, and he enjoyed immense public popularity. At his peak, he was probably the most popular American celebrity of his time. In 1907, crowds at the Jamestown Exposition thronged just to get a glimpse of him. He had dozens of famous friends, including Booker T. Washington, Nikola Tesla, Helen Keller, and Henry Huttleston Rogers. Fellow American author William Faulkner is credited with writing that Twain was "the first truly American writer, and all of us since are his heirs."