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.
The final book of the law, mostly written by Moses (possibly finished by Joshua or a later writer). It ends with a very sad song by Moses telling Israel that they will inevitably forget God, follow idols, and be given up to their enemies until they return to God, which is exactly what happened.