When you’re raiding in England in Assassin’s Creed Valhalla, you’ll find plenty of wealthy points of interest that will do well to increase the reputation and size of your settlement. You want to raid often to explore and grow. But you’ll likely encounter books of knowledge that Eivor can read to better themselves, giving them access to more abilities they can use during combat. There’s a book of knowledge you can find under the Isle of Ely Monastery, and getting to it can take a bit of time.
You want to focus on raiding the Monastery first before grabbing the book of knowledge. It saves you time and lets you focus on obtaining it. Once you’ve cleared the monastery, you’ll notice the book is directly under the center of it. Unfortunately, searching any of the buildings and structures inside the area does not reveal any secret entrances or destructible items to reveal a path below. Even the well is blocked off, and you can’t open it.
Instead, to find the book’s cave entrance, you need to the east of the Monastery and ook for a small cave. The cave entrance is pictured above, and the exact location of the cave on the map is down the hill from the monastery.
Proceed inside the cave and go through. There will be a handful of doors you can break down that is blocking your path, and after you destroy them, the book is yours. It gives you the melee ability called Dive of the Valkyries. It allows Eivor to jump into the air and then come crashing down on them.