Samuel Langhorne Clemens (November 30, 1835 – April 21, 1910) was a Human who lived on Earth during the 19th and 20th centuries. Better known as Mark Twain, he was one of the most noted American authors of this time period.
Samuel Clemens met several members of the crew of the USS Enterprise-D in 1893 when several of them were transported back to that year. Clemens followed them back to the year 2369, where he was given a tour of the Enterprise by Deanna Troi, who convinced him that his pessimism about the future of the human race was unfounded. Clemens returned to 1893 to help Jean-Luc Picard return to the 24th century, and to settle their accounts in the past. When Picard told Clemens that he wished he could have gotten to know him better, Clemens advised him to read his books as they contained everything that he was. (TNG episode: "Time's Arrow")
At a student "meet-and-greet" at Starfleet Academy, Cadet Elizabeth Shelby, upon seeing all the Academy uniforms, found herself reminded of a Twain quotation: "Clothes make the man. Naked people have little or no influence on society". (NF novel: Stone and Anvil)
Jake Sisko read several of Clemens' works as a pre-teen. He was especially fond of The Adventures of Huckleberry Finn, so much so that his father Benjamin called him "Huckleberry". (DS9 novelization: Emissary)