What is the procedure if you want to set a story in a world created by someone else?
If, after reading someone else's novel I came up with some neat plot that would fit into that novel's world, but would be a separate story from the original, with maybe some peripheral contact with some of the originals characters; is it allowed? Can I do it without explicit permission (I think doing this would at the very least be extremely discourteous)?
My gut-feel is that it involves some kind of IP that requires permission/deal of some kind.