Many of us will accumulate vast libraries of digital books and music over the course of our lifetimes. But when we die, our collections of words and music may expire with us.

Someone who owned 10,000 hardcover books and the same number of vinyl records could bequeath them to descendants, but legal experts say passing on iTunes and Kindle libraries would be much more complicated.

And one’s heirs stand to lose huge sums of money. ‘I find it hard to imagine a situation where a family would be OK with losing a collection of 10,000 books and songs,