Schemes of the Lich King
Shadow Prophecy, Book IV
Whereas there are rumored to be anywhere between 6 and 9 volumes of this baleful series, there are rumored to be only a small handful of copies of any given volume in existence. While it is true that scholars postulate that some wicked danger occurs if and when all volumes are assembled together, this has not been accomplished in at least a 1000 years. The various volumes of the Shadow Prophecy speak to a wide range of topics, all concerned with apocalyptic times and how to stop them (or, perhaps, how to initiate them).
Book IV concerns itself with demonology and the lost city of Darkveil. A copy was found in the prison of the Archmage, near the ogre magi prisoner, Coldrage (or Koldrag, as he later polymorphed into). When he was rescued by the adventuring party of Suriveth Varune, Ellyna Dirkane, Draco Kilvesh and Kouro Marmai, he brought the text with him.
He did speak of why it was so important to have him along as a guide – the book had certain arcane dangers that would afflict the uninitiated should they handle it without proper training.