The Collection of Dragons and Snakes is a new world mission in the new Enkanomiya area in Genshin Impact. Enkanomiya is a new location introduced in version 2.4 and brings tons of new world missions like this to the table. Make sure you switch to Evernight before starting this mission.
The world mission is found here, in The Narrows. Talk to the spirit pictured below to begin the quest, where you will be assigned the task of collecting five lost books.
The five books are scattered all over the place. Some are rewards for other missions and some are not even in Enkanomiya. Here's where you can find the five lost books.
Before the Sun and the Moon
Get this book as a reward in the Antigonus mission. Note, you don't have to complete this mission all the way. You will end up with the book halfway through the search.
Hydrological studies in Byakuyakoku
This book is obtained as a reward from the Date's Challenge mission. Once the mission is completed, you will get the reward.
The Serpent and Dragons of Tokoyokoku
This book is easy to find. Teleport to Inazuma City and head to Yae Publishing House. You can buy the book for only 1.500 Mora.
In the light, under the shade
To collect this book, you have to solve some kind of puzzle. Make sure Enkanomiya is in Evernight before proceeding. Find this Ruin Guard pictured below. You can recognize him while he is sitting next to two exploding barrels.
There is a triangular mechanism that glows blue to your right. Hit it. Change the time of day to Whitenight. (There is a time of day machine south of the hidden room.) The previously shut down triangular mechanism will now be hit.
Hit the second triangular mechanism. There is an exquisite chest in the room you just unlocked, but it won't give you the book. You will notice that there is a bright yellow light above the chest. She goes back and goes back to Evernight. Go back to where the exquisite casket was.
The bright light has now disappeared. Climb the wall. After activating the Seals, it will light up with a pattern. Store these patterns or use the image for reference below. You will need to go to a location and activate an altar model in the correct order.
Now teleport here to the Heart of the Serpent.
If you recognize the patterns above, you should be able to proceed. Enter the blue walls in the order listed above. (There will already be bright lights there - ignore them!) Once the puzzle is solved, a chest with the book will appear.
Record sperimentali di Bathysmal Visap
The final book will require you to complete the Tricolor File world mission. Upon completion of the mission, you will get the book.
Now you can return the books to Ema. Return the books to their original locations. An image frame will change. You can remember the books and get a luxurious chest and a key seal.