The Adabal-a was written by Morihaus, a winged man-bull who was an early cultural hero of the Cyro-Nordics. The book is considered to be the memoirs of Morihaus, consort to Alessia and Taker of the Citadel.
Found in the following locations:
Thalmor Embassy, Elenwen’s Solar, on a bookshelf north on the middle floor.
The Katariah, on a bookshelf in the emperor’s quarters.
Players who own the Dawnguard DLC can also find it in Volkihar Keep, on a bookshelf in Harkon’s quarters.
Reading by Steve (@thedicenerd)