Books can be attributed to "Unknown" when the author or editor (as applicable) is not known and cannot be discovered. If at all possible, list at least one actual author or editor for a book instead of using "Unknown".
Books whose authorship is purposefully withheld should be attributed instead to Anonymous.
These are message from the Universal House of Justice in Haifa Israel, elected from all the Baha'is from around the world. The highest governing body in the Baha'i Faith.