Payne translations, have extra volumes appended to the original 9. The total is 15. Not all sets include different of the last 6. Volume 3 of 15 is the same as volume 3 of 9
Books can be attributed to "Anonymous" for several reasons:
* They are officially published under that name * They are traditional stories not attributed to a specific author * They are religious texts not generally attributed to a specific author
Books whose authorship is merely uncertain should be attributed to Unknown.