> Does that mean they would frown on (and hence not authorize) any kinds of Tolkien-related literature?

You'd better believe it. There's this little thing called "copyright" and unless you own it, you can't publish anything. I'm afraid the Tolkien estate is very protective of this, as well it should be.

However, there's no harm in continuing to write fan style fiction based on Tolkien. But it will have to be for your own private purposes and use. Delight your children with it! It may inspire them to become writers, too. And they will =truly= appreciate that when it comes to taking their first composition class in college!