Copyright is easy when it's obvious...
Not so much otherwise... I'm trying to find out the copyright status of a book originally written in 1916 and republished (fifth edition) in 1925 in the UK.
The publisher has disappeared into another printing company about which I can discover nothing, though Companies House indicates that it no longer exists.
I can't locate a lineal descendant of the author - online genealogy is a joke - though I still have a query or two awaiting responses. Google Books admits of its existence but provides no view and no copyright information...
The problem is the whole life of the author (fair enough) plus seventy years... say what? Who does that benefit beyond Disney (other multinational copyright conglomerators are available)?
My best guess is that the copyright still exists with the estate of the author, but I can't locate said estate. I can't even prove the year the author died (I suspect 1953 or soon after, but I can't show it). If I can find the estate, I can ask. If I can find a date of death, I can wait. But, well, I can see why Gutenberg have their rules... it's a nightmare.
At least it's obvious if you're streaming current films or music; there's little excuse there. But vintage stuff?
(if you're interested in WW1 recipes: https://github.com/nailed-barnacle/A_Yorkshire_Cookery_Book )