Twain, Mark: - MARK TWAIN (1835-1910), pseudonym of Samuel Langhorne Clemens, was an American writer, entrepreneur, publisher, and lecturer who became one of America's greatest and most popular writers. Twain was born in Florida, Missouri, and grew up in Hannibal, Missouri, the state which influenced much of his writing. Twain acquired fame for his travel stories such as Life on the Mississippi (1883), and for his boyhood adventure novels The Adventures of Tom Sawyer (1876) and Adventures of Huckleberry Finn (1885).