Book tiles are changed between US & UK editions for marketing purposes. James Herriot's books had entirely different tiles. Due to many of the language issues mentioned in this thread & spelling differences some books do have different US & UK editions. I think it's mostly in popular works. It would be interensing to compare books where different English & American editions are noted.
Copyrights in one country are recognized in others that conform with the international copyright conventions. This has been the case since sometime in the last 50 years so the copyright issue referred to above used to apply, but so far as I know, no longer.