Mark Twain was born Samuel Langhorne Clemens on November 30, 1835, during a visit by Halley's Comet in Florida, Missouri. He grew up in Hannibal, Missouri which would later be the setting for "Tom Sawyer" and "Huck Finn." He became a master riverboat pilot on the Mississippi River and a typesetter at his older brother's newspaper. While working as a reporter in 1865, he wrote "The Celebrated Jumping Frog of Calaveras County" and became nationally recognized.

He served in a Confederate unit in the Civil War for a total of two weeks until the group disbanded, then married Olivia Langdon in 1870. Through his wife, he became friends with Harriet Beecher Stowe, Frederick Douglass and Nikola Tesla. He also knew Thomas Edison and patented three inventions.

The pseudonym Mark Twain came from an old riverboat call, "by the mark twain," meaning "according to the mark, the depth is two fathoms," or "The water is twelve feet deep and safe to pass." Previous to that, he had used the names "Josh" and "Thomas Jefferson Snodgrass."

Twain made a great deal of money by writing and even started his own publishing house, printing the biography of Ulysses Grant. Eventually, that and poor investments in technology caused him to go bankrupt, but he was able to recover by giving a series of world-wide lectures.

In 1909 Twain predicted that, since he had come in with Halley's Comet, he would leave with it as well. He died of a heart attack on April 21, 1910, one day after the comet's approach to Earth. He is buried in Woodlawn Cemetery in his wife's hometown of Elmira, New York.