Samuel Langhorne Clemens (November 30, 1835 – April 21, 1910), better known by the pen name Mark Twain, was an American author and humorist. Twain is most noted for his novels Adventures of Huckleberry Finn, which has since been called the Great American Novel, and The Adventures of Tom Sawyer. He is extensively quoted. During his lifetime, Twain became a friend to presidents, artists, industrialists, and European royalty.

Twain enjoyed immense public popularity. His keen wit and incisive satire earned him praise from both critics and peers. William Faulkner called Twain "the father of American literature".

Samuel Langhorne Clemens was born in Florida, Missouri on November 30, 1835 to a Tennessee country merchant, John Marshall Clemens (August 11, 1798 – March 24, 1847), and Jane Lampton Clemens (June 18, 1803 – October 27, 1890). He was the sixth of seven children. Only three of his siblings survived childhood: his brother Orion (July 17, 1825 – December 11, 1897); Henry, who died in a riverboat explosion (July 13, 1838 – June 21, 1858); and Pamela (September 19, 1827 – August 31, 1904). His sister Margaret (May 31, 1830 – August 17, 1839) died when Twain was three years old, and his brother Benjamin (June 8, 1832 – May 12, 1842) died three years later. Another brother, Pleasant (1828–1829), died at the age of six months. Twain was born two weeks after the closest approach to Earth of Halley's Comet.