The letter in which the story was found, dated 5 September 1936, was donated by Hans Jahnke, son of Giorgio Joyce's second wife, Asta, to the Zurich James Joyce Foundation. The Foundation has called its publication an "outrage", stressing that it has not granted permission for the book's release."We have been completely overlooked and ignored. It's only common decency to ask the owner," said the Foundation's Fritz Senn. "We are outraged. We have had no hand in this unfair thing and feel not just ignored but cheated."Although the published works of Joyce entered the public domain in Europe on 1 January this year, Senn says it has not yet been determined whether the non-published material is now out of copyright as well. "Copyright has been lifted only, we believe, from the published material. All the huge amount of non-published material we believe is still under copyright, so this is, we believe, an infringement of that," he said, adding that he is concerned the "very belligerent" Joyce estate might sue. "We haven't heard from them [but] what I'm afraid of is that with the large amount of copyright taken away from them, their remaining territory will be defended even more fiercely."

http://www.guardian.co.uk/books/2012/feb/09/james-joyce-childrens-story-cats-copenhagen