Book(s) of Discipline and Document(s) of Attainment Locations
Written by Uninvented
Book of Discipline (BoD) and Document of Attainment (DoA) will be found throughout mid-late game. You will find enough DoAs, but unfortunately they don't come until the end of the game, or near the end of the game. If you become too curious to reach the Secret Classes that the DoAs give you, you can always go into the CAP shop if you have enough CAP to purchase the DoAs.
REMEMBER THIS VERY IMPORTANT THING:
You must buy the Ancient Key for 150 CAP in the CAP Store. The Ancient Key allows you to enter the Ancient Underground Path and the Ancient Labyrinth. In the Ancient Underground Path is where you will find two of the seven BoDs and two of the three DoAs.
The BoDs are 50 CAP each. The game only provides us with seven BoDs. You can beat the game with the seven, but it is a fun challenge to get all the Classes and see what they do for the team.
You will need to buy five BoDs if you want each member of your party to learn all the Classes. There are a total of four base Classes, three for each party member. Earning the 250 CAP to purchase the BoDs from the store isn't a problem to do.
The DoAs are 100 CAP each. If you've done an immense amount of grinding, or if you plan to, you may end up with enough CAP to buy what you need from the store without spending any cash. This way, you don't have to wait till the end of the game before your chars attain all the Secret Classes- if that's how you prefer to do it.
Don't worry about earning enough CAP. At a minimum, you will have enough to purchase the five BoDs and the Ancient Key. The total will be 400 CAP for those, which is 4,000 enemy kills. Not 4,000 battles; just 4,000 enemies. You'll do it.
IMO, it's a problem waiting so late in the game to get the BoDs and the DoAs. What's the point?!? (Maybe that's just me. Always the impatient one.) If you don't mind grinding, getting all the Books and Documents at a good stage of the game isn't beyond the realm of possibility.
I think a good place to have at least three BoDs is immediately before, during, or after The Forest of Trials. In The Forest of Trials, you gain your second BoD. If you can get the third one around the same time, you'll be able to change Classes on all three party members at or near the same time.
The first BoD is from Milka's Villa. You can't do anything with it just yet. You have to get through Iatt Path and reach the town of Iatt where Classes are changed.
The Forest of Trials is immediately following your visit to Iatt. Essentially, you gain two BoDs back-to-back. When you get to Iatt, you can change one char's Class (since you'll have the BoD from Milka's Villa.)
Or, if you're patient, you can hold off a little longer to get the second BoD soon and then just buy the third with your earned CAP. If you're the impatient type, then go ahead and buy four BoDs. You may have enough CAP to do it. You can achieve two Class changes for each char quickly that way.
It's ok to buy four BoDs and do the Class changes since you have to buy five BoDs anyway if you want all Classes for each character.
If you look at 1OldTymer's Class List under the Game Pages you will see at what Level the chars earn their final skills/Magic spells for each Class, because you'll want to reach that Level at a minimum.
If you're eager to get to the next Class change, at least wait until you gain all the skills and spells for each Class. Level 30 is the minimum you need to reach for each Class. Level 36 is as high as you need to go in order to learn all skills and spells, but you can go as high as you'd like.
Your Levels aren't an issue for the Special Classes, since your chars will remain in those Classes till you complete the game.
Class changes increase Levels incredibly fast. I do recommend you don't change the entire party at the exact same time. You will be grinding for XP in areas with stronger enemies. Class changes lower all your stats.
So starting out, your team will be weak if they all change Classes together. And you're all gonna die. Change the Class of one, or both, of the girls first. (Only because they take a little longer to reach the higher Levels to earn all skills.)
You will still have 1-2 strong party members, so you can grind anywhere you want without worry of being defeated. Get the party member with the newly changed Class to at least Level 11, then you can change the rest of the team's Classes.
Be warned: say you want to return to a Class because you discover you didn't learn all the skills. Once you buy a BoD or DoA, you don't own them. They are consumable items. They are not permanent.
Therefore, if you return to a Class, be it Base or Secret, you will need another appropriate BoD or DoA and your char will have to start from Level One again. So make sure that when you are about to change Classes, you are really ready to do it.
If you do plan on having all your chars learn every Class, then make sure you do all the Base Classes before you do the Secret Class. Save that one for last, even if you are anxious to attain it. That way, you won't have to buy another DoA for 100 CAP to end up with the Secret Class as a final Class change.
When you change Classes, you will not lose your original Special Skills or Magic. You will lose any skills and Magic you learned with previous Classes, but only temporarily.
Knowledge can't be erased, but you do have to be "strong" enough to invoke learned skills and spells. As your Levels increase with each Class change, you will regain the Skills and Magic you learned in previous Classes once you reach the Levels you originally learned them.
°•°•° Loka: Grand Sorcerer Knight °•°•°
°•°•° Sarna: Valkyrie °•°•°
°•°•° Kuril: Great Witch Girl °•°•°
Much of the following info is from "Rocketjess." I filled in some blanks. See Rocketjess' info at https://gamefaqs.gamespot.com/3ds/179778-chronus-arc/faqs/73109
Book of Discipline Locations
1. Milka's Villa: dropped from Geppel
2. Forest of Trials: across wide chasm
3. Bird Golteth drop: Duty #38 from Iatt Guild
4. Galbure's Tower, B1F: after block puzzles, right of large room
5. Ancient Underground Path, B11F: floating island area
6. Ancient Underground Path, B13F
7. Ancient Labyrinth, B10F, Treasure
Document of Attainment Locations
1. Underground Path: left from start, behind block puzzle.
*(Per 1Oldtymer) If you wait till later in the game to get this treasure, (which you shouldn't), it will be guarded by the Knight's Soul (which is Duty #40 from Bagas' Guild).
2. Galbure's Tower, B5F, side passage
3. Underground Path, B15F: Ancient Evil Dragon boss.*
*A possible drop. If you battle him enough (for 90K XP each time 😍) it'll drop at some point.