The Tower of Knowledge has a library shelf with six empty slots. Nothing tells you which books go there or in what order. Mightythorn's "Library Books" guide on Steam and Sdaknight's Chinese 100% guide both list the same six books in the same order, so we treat it as confirmed.
What order do the books go in?
From left to right:
- The Great Work IV – Rubedo
- The History of Dragons
- Dams and Weirs
- Upim's Fairy Tales
- The Old Ones Beyond
- Koko's Sapphic Adventure
Sdaknight's guide says the shelf opens a storeroom, and Mightythorn describes claiming a lance from a statue there. Returning every lost library book also unlocks the achievement "I'm Not Paying the Late Fee" (listed in Digitol's guide).
Where are the six books?
| Book | Where (Mightythorn unless noted) |
|---|---|
| The Great Work IV – Rubedo | Island cliff below the Cemetery: a cave with an egg outside. At the bottom of the stairs, it is on an altar to the right of the throwing weapon in the middle of the room; reach it with air dashes |
| The History of Dragons | Given by Wourha, the Knowledge Keeper, once you have catalogued enough enemies. SquidRadio got it from Wourha after clearing the flesh walls |
| Dams and Weirs | In the bookcase next to the teleporter, bottom shelf. SquidRadio also finds it on the bookshelf near the Wing Shrine |
| Upim's Fairy Tales | Hard to reach: from just outside the ramp to Obmuer Temple, three air dashes from right to left lead to a very dark area. Drop down a hole and dash straight onto the upper ledges; it lies next to a skeleton and a food item. Sdaknight describes dropping through a large tree hollow and flying out about a third of the way down |
| The Old Ones Beyond | Through a secret wall above the entrance of the library room; a skeleton holds it and drops it when killed. SquidRadio found it behind a hidden wall reached from a table |
| Koko's Sapphic Adventure | In the same room as Wourha; SquidRadio grabbed it from the bookshelf near the door |
Mightythorn warns that the area with Upim's Fairy Tales is dark and the enemies are tough, and that if you fall too far you need a Crystal or stone fragment to try again. You will want three dashes for it.
What about the other book slots in the Tower?
Some books are keys rather than collectibles. On the 2nd-floor entrance room, a bookshelf gap opens a secret door when you insert any one of these: Bone Machine, The End of Epha, the Ratty Bug Compendium or How to Serve Humans (Sdaknight). SquidRadio uses the Ratty Bug Compendium from the island and reminds you to take the book back afterwards. Another bookshelf near the Forbidden Archives works the same way and leads to a Meal Ticket.
What are the god books?
After you take the lance, Mightythorn notes a new book on the right: Wodaso's Embrace. Sdaknight lists the same book inside the storeroom. It starts a second set of four "god books":
- Wodaso's Embrace — the library storeroom.
- The Rotting God — Obmuer Temple, past a secret door above a skeleton pointing upward in the first dark room; drop down the hole and keep left.
- Monarch of the Void — through the Tower basement past the last flesh face, down to a room of statues; a secret passage in front of a skeleton by a pillar leads to it.
- The Green Goddess — from the cook Gagi's room in the Mausoleum, a secret door by blue torches leads into Verdant Hollow; it lies on a stone next to a Josami Warden.
These go in a cage room in the Record of Sin, reached with five-dash jumps from the Ancient World. Mightythorn's order from left to right: The Green Goddess, The Rotting God, Wodaso's Embrace, Monarch of the Void. The reward only becomes available after you beat the boss at the top of that tower. This second puzzle comes from one guide only, so it is to be confirmed.
More on the area itself in the Tower of Knowledge walkthrough.