Mark Twain was born Samuel L. Clemens in Florida, Missouri on November 30, 1835. He worked as a printer for a time, and then became a steamboat pilot. He traveled in the West, writing humorous sketches for newspapers. In 1865, he wrote the short story, The Celebrated Jumping Frog of Calaveras County, which was very well received. He then began a career as a humorous travel writer and lecturer, publishing The Innocents Abroad in 1869, Roughing It in 1872, and, co-authored with Charles Dudley Warner, Gilded Age in 1873. His best-known works are The Adventures of Tom Sawyer (1876), Mississippi Writing: Life on the Mississippi (1883), and The Adventures of Huckleberry Finn (1884). He died of a heart attack on April 21, 1910.
Justin Kaplan was born in Manhattan, New York on September 5, 1925. He received a bachelor's degree in English from Harvard University, followed by graduate work in the field there, but he left before earning a doctorate to work as a freelance writer and book editor. His first book, Mr. Clemens and Mark Twain, won the Pulitzer Prize for biography in 1967 and a National Book Award. His other works include Lincoln Steffens: A Biography, When the Astors Owned New York: Blue Bloods and Grand Hotels in a Gilded Age, and Walt Whitman: A Life, which won a National Book Award. He also wrote books with his wife Anne Bernays including The Language of Names and Back Then: Two Lives in 1950s New York. He was the editor of Bartlett's Familiar Quotations. He died from complications of Parkinson's disease on March 2, 2014 at the age of 88.