A pseudonym of Samuel Langhorne Clemens American writer and humorist, whose best work is characterized by broad, often irreverent humor or biting social satire. Twain's writing is also known for realism of place and language, memorable characters, and hatred of hypocrisy and oppression. Born in Florida, Missouri, Clemens moved with his family to Hannibal, Missouri, a Mississippi river port, when he was four years old. There he received a public school education. After the death of his father in 1847, Clemens was apprenticed to two Hannibal printers, and in 1851 he began setting type for and contributing sketches to his brother Orion's Hannibal Journal.