Thaelin's Notebook

Thaelin's Notebook contains the working notes and secrets of engineer Thaelin Darkanvil from the last five years. Within are manufacturing techniques, schematics for new inventions and a quantity of embarrassing doodles.

Source
This item drops from Overlord Blackhammer in the Iron Siegeworks in Frostfire Ridge.

As a quest objective

 * Privileged Information