He spent the last decade of his life toiling over his autobiography and demanding it not be published until 100 years after his death.
That day has finally come.
U.C. Berkeley will publish the first volume of the book this fall.
Mark Twain wrote such classics such as "The Adventures of Huckleberry Finn," "Tom Sawyer," and "The Prince and the Pauper."
As to why Twain wanted to delay publication of his memoir, scholars speculate it was to let him speak candidly, something he apparently did.
The book apparently contains some salacious details, including a long section in which Twain blasts his secretary with whom he had a tumultuous relationship.
One historian calls it quote, "400 pages of bile."