For an interesting view of how complex copyright law has become, see the following, keeping in mind that Mark Twain’s Autobiography has this back-story, from the Mark Twain Papers and Project:
“…At the time of his death in 1910, Mark Twain left his last major literary work—an autobiography—unpublished and stipulated that the entire unexpurgated work should not be issued for at least a hundred years after his death. In November 2010, the year that marks the centenary of Twain’s death, UC Press has issued the first volume of a complete three-volume critical edition of the autobiography, edited by the staff of the Mark Twain Project. A digital edition with a complete textual apparatus—not included in the print version—is available at the Mark Twain Project Online….” (Link to full website.)
Read on …:
Copyright Law and Mark Twain’s Autobiography (from LibraryLaw):
Excerpt: “… I told the story of Mark Twain’s copyrights on page 44 of “Copyright & Cultural Institutions” (http://hdl.handle.net/1813/14142) – though I did not speak specifically to Twain’s autobiography. At the heart of the story is the fact that Berkeley offered for sale in 2001 a microfilm set that apparently contained the Autobiography. I can’t see that anyone actually bought the microfilm set, but by offering it for sale, California extended the copyright on the manuscript until 2047….” (Link to full blog post.)