What is the true name of mark twain?

The true name of the author commonly known as Mark Twain is Samuel Langhorne Clemens. Clemens used other pen names including "Josh" and "Thomas Jefferson Snodgr". The name Mark Twain comes from Clemens' time working on river boats. The riverboatman's cry was "mark twain" or, more fully, "by the mark twain", meaning "according to the mark [on the line], [the depth is] two [fathoms]", that is, "there are 12 feet (3.7 m) of water under the boat and it is safe to p".