At this page: http://www.marktwainproject.org/copyright.shtml (Mark Twain Project's copyright page), it states:
All words written or dictated by Samuel L. Clemens (Mark Twain) are in the public domain if they were first published before 1923. All words written or dictated by Mark Twain which were published between 1923 and 2002, and their copyrights renewed where required by law, are copyright © by Richard A. Watson and J.P. Morgan Chase Manhattan Bank as trustees of the Mark Twain Foundation, which reserves all reproduction or dramatization rights in every medium
So does anybody have a list of works printed after 1922, IOW Twain works that are apparently NOT in the public domain?
This is not just an "academic" question to me - I (very) recently made a book available entitled "Mark Twain's Greatest Witticisms, Wisest Aphorisms, and Sharpest Criticisms: 50 Years of Brilliance from America's Favorite Author", but it has been "suppressed" due to a question about whether all the material in it is really in the public domain.
You can see that it has a page on CreateSpace, but now says it is no longer available: https://www.createspace.com/6868989
This collection has material from "all over" Twain's work, from the 1850s to 1909. AFAIK, it was all published prior to 1923, but I'd like to see a list of what is "off limits" to know that for sure. - B. Clay Shannon