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.
I have owned Cambridge University Press' fine edition of David Norton's KJV since 2005, and I am glad to see that Penguin offers it in such an attractive and affordable version.