Amiens is in the northwest of Amienois.
The chest is inside a fenced off house.
You can jump onto the balcony from the house next door.
Pick up the key in the first floor. It's under one of the pots.
Now you can open the chest at ground floor.
Book of Knowledge: Goule Breath
Champlieu Ruins are northeast of Paris.
You can also pick up one of the keys for the Lutetia Bureau here.
Enter the ruins through an opening in the ground by destroying the wooden floorboards that are hiding it.
Open the Hidden Ones door.
Follow the corridor straight ahead to the movable shelf.
Pull the shelf torwards you until it can't be moved anymore.
Now use the slide through passage in the corridor, get passed the rats and slide out again on the other side.
You can now pick up the Book of Knowledge.
Compendium - 1
This chest is in a storage building.
The door needs to be forced open.
Compendium - 2
This chest is in a house in the middle section of Compendium.
The chest is locked.
The key is carried by a soldier in the church.
Compendium - 3
This chest is inside a small house next to the church.
Door needs to be forced open.
Compendium - 4
This chest is in the church.
Behind the altar.
Compendium - 5
Book of Knowledge: Golden Flame
The Book of Knowledge is in the church tower.
Climb up at the outside and you will find a shelf blocking the entrance to the tower.
Climb up another level, where you can get in.
There is a wooden floor that you can destroy.
Do so and climb down.
Here, smash the pots and move the shelves aside.
Destroy the wooden floor boards and climb down.
The Book of Knowledge is on the desk.
Epernay is in the southeast of Amienois.
The chest is inside a storage building on the second floor.
Shoot down the big storage bag to get inside through the window.
Once inside, smash the wooden wall in front of the chest to access it.
Meledus is in the east of the Amienois map.
The chest is inside the building at the northeastern wall.
The entrance is blocked by a movable shelf.
Go inside. In a small room is a gap in the wall, where you can shoot the items blocking the shelf.
Now you can push the shelf inside to get to the chest.
Gear: Wretched Scythe
Murmiliacum is northeast of Compendium.
Enter the mansion and go up the first floor to get the key in the bedroom.
Go to the back of the house.
There is a square basement access covered with wooden boards.
Destroy the woods and descend.
Here is the locked door you need the key for.
The room is full of rats.
Shoot the wooden box on top of the drain so they can escape when you attack them.
Move away the shelf and you have access to the chest.
Gear: Bloodied Scythe
Pontem Esera is a camp right at a Fasttravel Point.
The chest is behind a locked door at the top and back of the camp.
The Goliath is carrying the key.
Suessionum is east of Compendium.
The chest is in the storage building by the water.
The door is barred.
You can shoot it from the other side of the building to get inside.
Once in, destroy the wooden walls so you can move around the shelves to get access to the chest.