Abridged History of the 10th Age
Book of Poisons
A dark and evil treatise, the Book of Poisons was written some time prior to the War of Necromancy in the Eighth Age; this was during the latter half of that Age, after the overthrow of Lumiä Lord of Light by Ozmiandre the Red. Interestingly, while the battle between Lumiä and Ozmiandre was facilitated by one of Lumiä treacherous generals (Tharos the Necromancer), that same mage went on to become the Necromancer of legend, feared in story and song.
The Book of Poisons was written by Tharos or one of his underlings (possibly the traitorous elf-mage who served as his second and spy) and details the rise to power of the Necromancer and the doctrine of his evil cult. Those who worship the Necromancer do so in the guise presented by the Book of Poisons.
The Book is generally feared and despised throughout the North. Even owning a copy of it is seen as evil and despicable, and being caught with one on your person is grounds for execution in most civilized lands.