I got my degree in English with a concentration in literature, and Twain was easily one of my favorite authors. Tom Sawyer delighted me, Huckleberry Finn challenged me every single time I read it for a class (which was more than once), A Connecticut Yankee in King Arthur's Court amused me. I enjoyed his stories of working on a riverboat in Old Times on the Mississippi, and I remember laughing so hard my stomach ached when I read several of his essays, especially "Fenimore Cooper's Literary Offenses" and "The Awful German Language."
Although Twain did leave instructions that his autobiography was to be published a century after his death, in reality parts of it have been published over the years -- some even before his death, in 1906-07. There were a few editions after his death, too, in which editors tried to "fix" Twain's meandering writing style. According to this article in the New York Times, about half of all the material in all three volumes haven't ever been published, although the percentage in the first volume is much lower (only about 5 percent).
I wonder if the reduction in price on the first volume means that the second will be out soon. In any case, I'm happy to finally have been able to get the ebook of the first at an affordable price, and I'm very much looking forward to reading it!