Wallace J.McLean writes:
The benefit, of course, is that once the death date of an author is conclusively determined, then, barring wrinkles like collaborators, translators, co-authors, illustrators, and posthumous publication, all of that author's works are, by definition, cleared.
And what about the myriad series that were basically contracted by the publisher, and each one was "authored" by the publisher's chosen pen name? Is that considered anonymously authored?
No, that's considered pseudonymously authored! If the true identity of the author is not, has not been, and cannot reasonably be known, then the publication+50 rule kicks in. This was recently confirmed under Canadian law in a decision by the Copyright Board. If there's authority for the statement that John Smith was the true author of "Johnny and the Skyship" by "Charles Vander Pelt", published in 1939, then the life span of John Smith determines the duration of the copyright. If John Smith died in or before 1954, the work is public domain in Canada; if he died after 1954, it is still under copyright. If, on the other hand, there is no authority anywhere for the true identity of the author of "Johnny and the Skyship" by "Charles Vander Pelt", published in 1939, then the work is public domain under Canadian law, and has been since January 1, 1990. The work is NOT public domain in the US or any life+70 country that also has publication+70 for pseud/anon works.