Mark Twain, born Samuel Langhorne Clemens, was a prolific American author and humorist. Twain is best known for his novels The Adventures of Huckleberry Finn (1884), which has been called "the Great American Novel", and The Adventures of Tom Sawyer (1876). He is extensively quoted and was a friend to presidents, artists, industrialists, and European royalty.

Twain was raised in Hannibal, Missouri, which later provided the setting for both Tom Sawyer and Huckleberry Finn. He served an apprenticeship with a printer early in his career, and then worked as a typesetter, contributing articles to his older brother Orion Clemens' newspaper. Twain then became a riverboat pilot on the Mississippi River, which provided him the material for Life on the Mississippi (1883). Soon after, Twain headed west to join Orion in Nevada. He referred humorously to his lack of success at mining, turning to journalism for the Virginia City Territorial Enterprise.

Twain first achieved success as a writer with the humorous story "The Celebrated Jumping Frog of Calaveras County," published in 1865. As his fame grew, Twain became a much sought-after speaker. His wit and satire, both in prose and in speech, earned praise from critics and peers.

Although initially supportive of American interests in the Hawaiian Islands, Twain later became vice president of the American Anti-Imperialist League, opposing the Philippine–American War and colonialism. Twain's financial ventures often failed, leading to bankruptcy, but he eventually overcame these setbacks with help from Henry Huttleston Rogers. He died a day after Halley's Comet was closest to Earth, fulfilling his prediction of going out with the comet.