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 first happened near Riga, a sea-port town in Livonia; where a multitude of people have seen in the open sky, A Coffin, Fiery Rods, Three Dead-Heads, A Serpent and Pyramid. the second was seen at Kirschberg, four german miles from the city of Elbing, and ten german miles from Dantzick; where, from the 6th till the 7th of may, 1763, these phoenomena stood for 48 hours with A Vehement Lightning And Thunder-Clap.