Tomes of Knowledge Quest/Spoiler

Requiments

 * The New Frontier Quest Completed. Otherwise Cael won't accept tomes.
 * Parcels or Levitate spell.

First Tome

 * Go to the orc camp located northwest of Zao and enter the fortress, when you are underground go north and west. You will meet all kind of Orcs (except Orc Riders and Orc Marauder) and maybe some high class Lizards or a Dragon Lord lured.

Second Tome

 * After unlock mission 2 - The maw of the Dragon - of the Uneasy Alliance Quest follow this way.


 * You will find the Tome (and the crystal) in the last floor of tower.
 * You can take second and third Tome at once.

Third Tome

 * During mission 7 of The New Frontier Quest.

Fourth Tome

 * After break the crystal (mission 2 of Uneasy Alliance Quest), go back to Curos and report your mission, you will recieve a Tome as a reward.

Fifth Tome

 * Inside lizard camp during mission 2 of Children of the Revolution Quest.

Sixth Tome

 * During mission 9 of The New Frontier Quest, near NPC Chrak.

Seventh Tome

 * During mission 5 of the Unnatural Selection Quest.

Eighth Tome

 * After completing mission 4 of Children of the Revolution Quest, go back to NPC Zalamon and you will receive a Tome as a reward.

Ninth Tome

 * During mission 5 of Children of the Revolution Quest, when you up the stairs, go south, the Tome is inside the building. Beware the Lizard Chosens, Eternal Guardians, Lizard Gate Guardians and some bosses that spawn in group (the bosses were not confirmed yet).

Tenth Tome

 * The Tome is located in a chest on the top floor of the highest tower in Zzaion, which is the furthest building to the south.
 * Note: The gates to Zzaion only open during an Orc raid on Zao. This is the only chance you have of gaining entry into the Lizard Fortress. A strong team is advised as there can be multiple Lizards, High Class Lizards and all kinds of Orcs attacking you at the same time.

Eleventh Tome

 * After give 8 Tomes to NPC Cael, you will be able to enter a secret hole, where you will find many Lizard Chosen, some Ghastly Dragons and a Tome.

Twelfth Tome

 * Zao Palace (Not Confirmed)

Rewards for handing the tomes into NPC Cael
1 Tome: Dragon Tapestry Allows you to buy Dragon Tapestrys from NPC Pompan for 80 gp each.

2 Tomes: Minotaur Backpack Allows you to buy Minotaur Backpacks from NPC Pompan for 200 gp each.

3 Tomes: Lizard Weapon Rack Allows you to buy Lizard Weapon Rack from NPC Esrik for 500 gp each.

4 Tomes: Rice Balls Allows you to trade Bunches of Ripe Rice for Rice Balls with NPC Swolt.

5 Tomes: Dragon Backpack Allows you to buy Dragon Backpacks from NPC Pompan for 200 gp each.

6 Tomes: War Drum & Didgeridoo Allows you to buy War Drums and Didgeridoo from NPC Cael.

7 Tomes: Snake Head Teleport Handing in 7 Tomes you will allow you to use the snake teleport at the peak of the mountain, inside of which Farmine is located, in order to get to the northern part of the Zaoan continent. This is a one-way teleport only!

8 Tomes: Corruption Holes Allows you to enter a hole in the north-eastern end of Zao, where you can find many Lizard Chosen as well as 4 Ghastly Dragon.

9 Tomes: Lizard Weapons Allows you to sell Zaoan Helmet, Zaoan Armor, Zaoan Legs, Zaoan Shoes, Drakinata, Sais, Zaoan Sword, Drachaku, Twin Hooks, Zaoan Halberd, Wailing Widow's Necklace and Beetle Necklace to NPC Esrik.

10 Tomes: Zao Palace Allows you to enter the Zao Palace. It is situated deep underground, below the mountain base of the Lizards. You will find Ghastly Dragons there, but before you get to them you will have to fight your way through hordes of Draken Warmasters.

11 Tomes: Dragon Statue Allows you to buy a Dragon Statue from NPC Cael after you bring him a Red Lantern.

12 Tomes: Dragon Throne NPC Cael will now make a Dragon Throne for you after you bring him a Red Piece of Cloth. There is a time limit on these items and he can only make them every so often.

More than 12 Tomes: If, by any chance, you are able to get more than 12 Tomes, you can still hand them in to NPC Cael. He will reward you with 5000 experience points for each extra tome you give to him, but still only one is allowed every 24 hours in real time.