Samuel Langhorne Clemens, better known by his pen name Mark Twain, was an American author and humorist. He is most noted for his novels, The Adventures of Tom Sawyer (1876), and its sequel, Adventures of Huckleberry Finn (1885), the latter often called "the Great American Novel."

Twain grew up in Hannibal, Missouri, which would later provide the setting for Huckleberry Finn and Tom Sawyer. He apprenticed with a printer. He also worked as a typesetter and contributed articles to his older brother Orion's newspaper. After toiling as a printer in various cities, he became a master riverboat pilot on the Mississippi River, before heading west to join Orion. He was a failure at gold mining, so he next turned to journalism. While a reporter, he wrote a humorous story, "The Celebrated Jumping Frog of Calaveras County," which became very popular and brought nationwide attention. His travelogues were also well-received. Twain had found his calling.

He achieved great success as a writer and public speaker. His wit and satire earned praise from critics and peers, and he was a friend to presidents, artists, industrialists, and European royalty.

He lacked financial acumen and, though he made a great deal of money from his writings and lectures, he squandered it on various ventures, in particular the Paige Compositor, and was forced to declare bankruptcy. With the help of Henry Huttleston Rogers he eventually overcame his financial troubles. Twain worked hard to ensure that all of his creditors were paid in full, even though his bankruptcy had relieved him of the legal responsibility.

Twain was born during a visit by Halley's Comet, and he predicted that he would "go out with it" as well. He died the day following the comet's subsequent return. He was lauded as the "greatest American humorist of his age," and William Faulkner called Twain "the father of American literature."