Hi again Henry,
Many thanks for the additional information.
Since you and the new publishers seem relatively content on the issue of your mother's title in the etchings, I won't say more about that. In any case that would involve the law on inheritance which is not really what this forum is about. And just as well really, because there's quite a lot to say about copyright and the US dimension.
But first, a mention about reversion again. I would tend to agree with your correspondent that, assuming a standard publishing contract was used, reversion, if it was mentioned at all, is likely to have been triggered by the works going out of print. The chances of the contract applying for the whole term of copyright are very slim, and if that proves to be the case, L was extremely poorly advised at the time she entered into the contract. But coming up to date, let us assume the worst case, namely that the original publisher still has full rights. Since they have not responded to your correspondence and asserted those rights, there may be a situation where something known as estoppel by acquiescence could work in your mother's favour later on. The
Wikipedia article on this explains it far more clearly than I could so I will only add that there is a sub-species of estoppel called laches which may also be applicable. Laches is said to occur when a rights holder A deliberately fails to take action to protect those rights, knowing that B is likely to infringe upon them, and does so in order that he, A, may benefit from damages to which he would not have been entitled had he asserted his rights at the appropriate time. This is pretty arcane stuff, and of course hopefully it will never be necessary to argue this, but the failure of the old publishers to engage with you is a positive thing in some ways.
So moving from the arcane to the downright convoluted, let's try to unravel the transatlantic copyright issues of the first publications. Although international copyright norms have been greatly harmonised, this was certainly not the case in the 1930s when the USA operated a very different system to that found in most of Europe, including the UK. That said the US and UK had a bilateral treaty which meant, in theory, that each country would provide the same protection to works created in the other as they would to works created at home, provided this did not exceed the protection available in the first country. In other would where there was discrepancy between the two regimes, the lesser of the two 'benefits' would apply. In practice the arrangement was anything but reciprocal, however that is a story for another day. There were a number of specific matters to consider, such as whether works were published 'simultaneously' (actually within 30 days of each other*) in the two countries, and where the published edition was printed, together with the need for the US edition to carry a copyright notice. But the major factor which affects L's books is that in the USA at that time, a work had to be registered with the US Copyright Office (USCO) to gain any kind of copyright protection within the USA; there were other formalities but they don't appear to be relevant here.
Before delving deeper into this, I am not entirely clear what you meant when you said "those books were published in the UK and the US in 2 consecutive years in the 1930s". Was there a year's gap between the two books, or between the UK and US publication in each case? If it is the latter, it will have a bearing on the US copyright, since it would mean that publication there was not 'simultaneous' and so the US edition would not be protected by copyright at all. There is a whole other area of complication regarding where the US work was typeset and/or the electro plates were made, but in order to keep this as simple as possible I won't go into that here. Should you wish to, you can read up on that subject in an entertaining paper by the American academic James L West III
here.
So to return to the main issue of US copyright itself, assuming that simultaneous publication had occurred, the work would have had to have been registered with the USCO there. The initial period of registration was 28 years, meaning that depending on the actual date of publication, copyright in L's books in the USA would have been secured until somewhere in the period 1958-1968. This is important because the later 1976 Copyright Act changed the system for calculating the copyright term, but it was not retroactive if the first period of registration had already lapsed by 1976. Continuing protection depended on the work being re-registered within the 27th year of the first term, which if successful, then extended copyright for a further 28 years (ie to roughly the period 1984-1994 in L's case) well within the effective date for the new provisions to apply. This is where the figure of 95 years from the date of publication comes in. However I am not at all sure that re-registration would have happened. It would have been up to the publisher to do this (and in any case L is likely to have died at around the same time it needed to be done) and since I suspect that the rights had already reverted at that point, or the publisher had lost interest in the books, there would have been absolutely no financial incentive for them to re-register the copyright. Of course they might also just have forgotten. The USCO did not send out reminders in those days. The USCO has said that less than 15% of all copyrights were re-registered in this period, and so it is probable that the US editions of L's books passed into the public domain there in the late 50s or early 60s. However things do not end there. One of the reasons that the 1976 Copyright Act came about was that after about two centuries of being outside the international copyright community, the USA was getting its legislation in line with the other major nations. Indeed by 1988 the USA had acceded to the primary international treaty on copyright known as the Berne Convention and so was obliged to amend the 1976 Act to afford the same rights to foreign works as to domestically produced works
without the imposition of formalities. 'Formalities' here means the legal requirement for registration, copyright notices and similar things, before protection comes into force. The consequence of this was that copyright in older foreign works (those created after 1923 and before 1976) was revived and the term then became 95 years from publication. However, if during the period that the works were in the public domain in the USA someone there had republished the books they would not retrospectively become liable for damages etc. Hopefully this did not occur in the case of L's books.
The USCO maintains extensive records of old registrations and many are available to
search online, so it might be worth checking. Even if the registrations for the relevant dates are not online, you can ask for a manual search to be done. Finding the registration details might throw some light on the matter of reversion.
And lastly, returning to UK copyright law, the business about 50 years after the death of an author comes about because prior to 1995 that was the rule here. But since L died in 1958, the old 50 year rule meant that her works were still in copyright in 1995 and so became subject to the new lifetime + 70 years term.
I hope things go well for your mother's operation.
*Strictly speaking, it was not the actual publication, ie books hitting the bookshops, that had to be within 30 days, but a deposit copy of the book and registration had to be accepted by the US Copyright Office within that period.