JK Rowling wrote and illustrated (by hand, herself) a limited edition of seven copies of a book of Harry Potter-related fairy tales - all but one as presents for family/friends. The last one was auctioned at Sothebys, with the proceeds going to charity.
Amazon paid four million dollars (nearly two million pounds sterling) for it and is showing off this beautiful object (for such it is, with silver and moonstones and vellum and more) so the mug punters like you and I can see it too (maybe a lot more than if it had been bought by a private collector without commercial interests).
www.amazon.com/beedlebard is where you can see The Tales of Beedle the Bard.
Her charity is one addressing the needs of vulnerable children in Europe.
Back in a few days - didn't get in enough of that basking...