World Tomes are a type of secret collectibles in The Serpent Rogue. This page explains: where to find and how to collect all the World Tomes and how to fill all the pages of the Journal. There are 15 collectibles, but you won't get any special reward for collecting them all.
World Tome I
You won't collect this tome at the beginning of the game, but only after obtaining the rat potion (or using the transformation statues in Wasteland). By digging under the wall next to the abandoned house, you will enter the attic, where you will find the tome.
World Tome II
This tome is in the left corner of the Abandoned House, behind the trunk by the fence. You have to cut it with the axe.
World Tome III
In the camp, go to the small building on the left, near the passage to Wasteland. The tome is on the table inside.
World Tome IV
There is a mound to the south of the forge, by the fence. Dig it up using a shovel.
World Tome XV
You will find this tome inside a bag hanging in front of the building at the northern border of the location.
World Tome XIII
After entering the Wasteland, head southeast to the corner of the map. Here you will find a tree trunk with the tome next to it.
World Tome XV
Right next to Tome XIII, in the right corner of Wasteland, you'll find another mound to dig up with Tome XV.
World Tome XI
This tome can only be collected after completing the maze in the northern part of Wasteland. Take an axe / torch and glass with you. The bag with the tome is on the right, by the rocks, near the exit from the labyrinth.
World Tome XII
The last tome in the Wasteland is in a chest inside the cave. To get to it, you first have to heal the tree, then go through the labyrinth in the north to get to the north-eastern cave visible on the map.
World Tome VI
In the Pier, in front of the destroyed cart, you will find a digging spot. That's where you'll find tome VI.
World Tome XIV
To get the 14th tome, you must go aboard the ship when it arrives at the port. The tome is on the deck.
World Tome V
The only tome in Undertaker is behind the graveyard, on the right, at the end of the path.
World Tome VIII
The only tome in the Church is to the east, by the lighthouse.
World Tome IX
In Mavka's Shelter, cross the water to the east to find the chest. The water is deep, so you need a transformation to go through it (a large animal or skeleton - Restless).
World Tome VII
In the swamps, you can find the tome after healing the Corrupted area in the north. There, you have to enter the water through the hole in the fence and go northwest. Use the mini-map to navigate underwater (you will also take damage).
World Tome X
The Swamp - Dobhar-chu's Lair - is one of the locked locations and one of those that you get access to only at the end of the game. There's a spot on the hill that you can dig up as a rat to find the tome.