How was retroactive copyright extension ever approved of? In the US, copyright has been retroactively extended multiple times. Steamboat Willie for example has repeatedly been snatched away from the public domain in the last minute. It was first due to enter the public domain in 1955. Then in 1986. Then in 2003. Last extension (that I know of) was until 2023 which is the year I write this. But at the same time, ex post facto laws are expressly forbidden by the United States Constitution. So how is it possible that ex post facto copyright extensions have been passed multiple times? As I see it the victim here is the general public. Is it simply that they haven't sued for rights? Or did they? If I sign a contract that I will hand over my poem to you in two weeks, can I just change my mind and say &quot;no, now it's three months&quot; whenever I feel like it? AFAICT that's exactly what's been happening here.
See Golan v. Holder (2012). This related to an extension of copyright protection for works that had already fallen into the public domain. an extension of copyright is still a &quot;limited time&quot; allowed by the Constitution historical practice, including by the first congress, is evidence that giving copyright protection to previously unprotected works is okay there is a rational basis that such extensions promote the progress of science fair use continues to be available as a defence/exception Further, no one is liable for copies of works made while a work was in the public domain. This was not imposing retroactive, ex post facto punishment. But see Justice Stevens's dissent in Eldred v. Ashcroft (2002) for such an argument—not in the punishment sense, but analogizing to a taking (the majority held that the Sonny Bono Copyright Term Extension Act was constitutional).
There is no copyright in an idea. A retelling of a story could be a derivative work, and the making of it a violation of the author's rights to authorize the creation of derivative works (17 USC 106 in US law. article 2 of the Berne Copyright Convention). However, the originals of most &quot;fairy tales&quot; are long out of copyright, and new versions of them may be created and published in any form, for pay or not, by anyone who chooses to do so. Some &quot;fairy tales&quot; are in fact original creations recent enough to still be under copyright protection. (at most 95 years in the US for works published before 1978, 70 years after the death of the author in many countries). In those cases a new version would probably be a derivative work, and require permission from the copyright owner. In some cases a particular author added significant elements to the plot of a fairy tale or folk tale recently enough that the version which introduced those elements is still protected by copyright. In any such case, a new version or retelling that included the new (protected) plot element might well be found to be a derivative work, and so require permission. Basing any retelling only on versions clearly out of copyright will avoid this problem.
I'm going to focus on one part of your question, because I think it is informative to the entire question: "By publishing those data in a copyrighted book are they now in the public domain?" Insofar as copyright is concerned, the "facts" are simply never copyrightable. What is copyrightable is the expression of the fact. So you publish a book and it contains many facts. You retain copyright over how you expressed the facts, meaning the word choice, format of presentation and so on. The discussion of this point always leads people to ask the following two questions: What if the "facts" are closely related to the way they are expressed? For example, a phonebook contains "facts" about phone numbers. The individual numbers are not subject to copyright. But if the way they were organized was clever (i.e. not merely alphabetical) the presentation may be copyrighted. Doesn't that line get blurred? Why doesn't "the presentation order" count as a "fact?" It does get blurred! And courts use nuanced case law and judgment to figure out which side of the line a given thing is. However, one backstop is that if AN EXPRESSION is so closely related to the IDEA BEING EXPRESSED that the IDEA cannot be otherwise expressed, then then the EXPRESSION is not subject to copyright protection. To answer your specific questions: The book is subject to copyright. The facts in the book are not. Someone else could publish a book with the same measurements so long as they are expressing the facts with sufficient difference from the original. I'm not familiar with CUSIP numbers. However, there are two things to say here. (A) it sounds like you are describing a contractual relationship between the people who have the numbers. This is not governed by copyright; it is governed by contract between the parties. If these numbers could be treated as a "trade secret" they might be protected IP in that way. But given that they are likely circulated at least a bit, they don't seem like candidates for "trade secret" protection. To your question, "what is the effect of one person leaking?" If "trade secret" law was doing any "work" here... then yes, the trade secret would be undone once the information was public. But like I said, its likely this is actually all about contracts not intellectual property protection. (B) The "facts" of "which number is associated with which instrument" is likely NOT subject to copyright at any time. The specific numbering code COULD BE copyrighted, but in reality is almost certainly TOO CLOSELY tied to the IDEA being expressed to be copyrighted. Could the number be expressed otherwise? If not, then its likely not protected by copyright. -- Big take away here: You seem to be confused about the concept of "facts" getting into the public domain. That's not exactly what copyright is about. Copyright would protect the expression of facts. An expression can become public domain if it is sufficiently old or if the creator designates it as public domain work. But simply "putting something out there" does nothing to alter the copyright status of the thing.
Copyright law is not based on contracts, and does not require agreement. No one may distribute copies of a copyrighted work without permission from the copyright holder. For instance, in the US, both Persons A and F can be sued because Title 17, Section 501 of the US Code says: (a) Anyone who violates any of the exclusive rights of the copyright owner ... is an infringer of the copyright or right of the author, as the case may be. (b) The legal or beneficial owner of an exclusive right under a copyright is entitled ... to institute an action for any infringement of that particular right committed while he or she is the owner of it. Copyright infringement isn't an issue of violating terms you agreed to with a private entity. Your duty to not infringe copyright was imposed by your country's legislature, who does not require your personal agreement to do that.
If the author died in 1946 then copyright in his works expired at the end of 2016. The work is in the public domain. The relevant section of the Copyright Designs &amp; Patents Act 1988 extends to the whole of the United Kingdom, but not Crown Dependencies or colonies. You need to be sure that the work is the author's own work. If someone else has contributed then the copyright endures until it expires 70 years after the death of the last of the authors. The same applies to art. If you want to reproduce artwork, say for a cover/sleeve design, that would also have the artist's copyright, which lasts for 70 years after that person's death. The typography of a book has copyright which lasts for 25 years from publication.
You misunderstand the nature of copyright. Holding copyright allows you to decide how the work can be copied: there is no obligation on you to publish it if you don't want to. After your copyright expires you don't have to publish it either: the only thing that has changed is you can no longer prevent anyone making a copy. The lost works of Aristotle are in the public domain - if you can find them you can make as many copes as you like.
One big hole in any scheme that relies on copyright is that it could not preclude people talking about the previous content or talking about you. This is well established First Amendment law. For example, see Near v. Minnesota 283 U.S. 697 (1931), which holds that except in rare judicially established exceptions (relating to military information, obscenity, and inciting acts of violence), government censorship is unconstitutional. Thus, no statutory scheme could be used to prevent third parties who happened to have seen the material while it was freely available from re-iterating what they had seen, or talking about it, or talking about the author (you). People could even reproduce portions of the published content. Some types of reproduction would be protected as fair use in the US, especially if the reproduction is for the purpose of criticism. (17 USC 107, and this previous Law.SE answer) The closest approach would be to protect your work as trade secret, making sure that anyone that you share it with agrees to non-disclosure. But, if you "publish unique content under this pseudonym" there is no way to "arbitrarily or wholly revoke discussion about that content". If the cat gets out of the bag, while you may have remedies against the person who violated the non-disclosure agreement, you would not be able to prevent third-party discussion or reproduction.
The basic principle is that copyright never protects an idea, it only protects the expression of an idea. In the US, that rule is embodied in 17 USC 102(b) which provides that: (b) In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work. When significant, detailed, and specific plot elements are copied from a prior work, then that may make the new work a derivative work. Creation or distribution of a derivative work requires permission from the owner of the copyright (if any) on the prior work (source work). But the elements used must be significant and must be detailed. If all that is taken could be expressed in a summery contained in a single sentence or paragraph, this will not make the new work derivative. For example, such ideas as: Napoleon meets the Emperor of China and they form an alliance. [My idea] Sherlock Holmes helps to repel the Martian invasion described in The War of the Worlds. Conan Doyle's Professor Challenger is also involved. [Wellman's Sherlock Holmes's War of the Worlds] Aliens crash land on Earth in 1905, creating an alternate timeline. They seek to start WWI early, to stimulate technical development. [Benson's ...And Having Writ] would on their own not be enough to constitute a derivative work and thus infringement. But the more specific detail from the source work is used, the more likely it is that an infringement suit would win. By the way, the rule is the same whether the source work is a book, or a TV show, or an opera, or any other work subject to copyright protection. If the work is old enough, any copyright will have expired, but the format of the original does not matter, as long as it is &quot;fixed in a tangible form&quot; which includes video tape, DVD, computer file, or a script written on paper. About the only things that do not count as fixed would be an impromptu dance, song, speech, or story whch the creator performed or spoke without its ever having been written down or recorded in any way.