"Mark Twain," a river measurement meaning "12-feet-deep," was the pen name of Samuel Langhorne Clemens, who died APRIL 21, 1910. Growing up on the Mississippi, he left school at age 12 when his father died, became a printer's apprentice, then piloted steamboats till the War between the States suspended river traffic. Clemens joined the Confederates, but after 2 weeks got discharged to work for his brother Orion, who was secretary to Nevada's Governor. After an attempt at mining, he became a reporter in Virginia City, Nevada, using the name "Mark Twain" for the first time. He moved to San Francisco, sailed the world, then married Olivia Langdon. His attempt at publishing failed and he paid off debts by lecturing across America. Mark Twain wrote: Huckleberry Finn, Tom Sawyer, Life on the Mississippi, Prince and the Pauper, Connecticut Yankee at King Arthur's Court, and Joan of Arc. His later success was unfortunately offset by nearly all his family dying before him. He talked Ulysses S. Grant into writing his Civil War memoirs. Answering Bible skeptics, Mark Twain said: "If the Ten Commandments were not written by Moses, then they were written by another fellow of the same name."