Librarian Note: There is more than one author by this name in the Goodreads database.
Samuel Langhorne Clemens, known by the pen name Mark Twain, was an American writer, humorist and essayist. He was praised as the "greatest humorist the United States has produced," with William Faulkner calling him "the father of American literature." His novels include The Adventures of Tom Sawyer (1876) and its sequel, Adventures of Huckleberry Finn (1884), with the latter often called the "Great American Novel." Twain also wrote A Connecticut Yankee in King Arthur's Court (1889) and Pudd'nhead Wilson (1894), and co-wrote The Gilded Age: A Tale of Today (1873) with Charles Dudley Warner.
The poem that succeeds the essay especially shows what a powerful intellect Twain had. It might seem strange to suggest that a man with Twain's reputation is underrated, but I think he somewhat is.