The next night.

Maiden's castle, in the basement.

[Hi, otherworldly creatures. Xiaowei had just opened her spell book, but closed it again.

[It's been a long time since you've called me an "otherworldly creature.] The girl said lazily.

Xiaowei was silent for a few seconds. It seemed to take a lot of effort for her to finally make up her mind.

[One thing,] Xiaowei plucked up her courage, [It's hard to say...... However, I want you to listen to it. 】

[What the hell is going on?] The girl was surprised.

You're also a spellcaster in your own world, right? 】

[Sort of. The girl said vaguely.

[I haven't seen a single ordinary person who would consider factoring and trigonometric functions as a compulsory course.] 】

[But this is indeed just compulsory education, Xiaowei.] I'll do a simple differentiation. 】

What is compulsory education? 】

[It's-] The girl felt a headache, [It's similar to a church school and an aristocratic school, you know? Teach every little one to read and count. Everybody is going. 】

[It turns out that the casters of your world have reached this level......

[No, no, why do you want to equate junior high school math with spellcasters!] Say...... Architects and the like need too! 】

It's over, and there is no way to communicate between scientific civilization and magical civilization.

[I know it's offensive,] Xiaowei took a deep breath, [But I hope you can...... What can you ......】

What can I do? The girl is inexplicable.

[You can reveal one or two of your world's spellcasting system to me!] Xiaowei's face turned red, [I understand that this is a secret for you, but ...... But ......]

The girl was stunned. Then, she smiled.

What spell casting system does she have to reveal...... It's hard not to give Xiaowei the periodic table back. Legendary Fa Fa Deleleev Mendeleev, hydrogen, helium, lithium, beryllium boron, carbon, nitrogen, oxygen, fluorine, neon, ......

It's good to think about that kind of thing.

Thinking about it, we know that this level of natural law cannot be universal in this universe. The protagonist in the time-traveling novel uses the scientific knowledge of the earth while casually using magic, which is just the novelist's words.

But......

Girls are not averse to telling some knowledge. It's just that I'm a liberal arts student, what can I say?

[What are you talking about, Xiaowei. I don't shy away from revealing a little bit of my hometown to the world. Well, only a small part of it. 】

[Because the casting method is not universal?] 】

[Because the knowledge that an individual can grasp is only a drop in the ocean.] In the face of civilization as a whole, the knowledge that an individual can possess is too small......]

The girl suddenly had an idea.

[I remember that we called several merchants from Yangyan City, and among them were booksellers, right? 】

[I will definitely give you a satisfactory book list, so that you can understand our civilization,] Xiao Wei said sincerely, "This is the only thing I can exchange with you." 】

[Then I'll write you a book classification list.] The girl said.

[What? 】

[Let me show you how the library buys books in my hometown.] The girl said confidently.

……

A moment later.

Xiaowei looked at what the girl had written on the parchment and didn't say a word.

Am I going too far? The girl thought to herself.

As a person who considers herself "literary and artistic", the girl carried a lot of inconsequential things in her previous life. For example, just to show off in front of her classmates, she memorized the rules for placing books in libraries at home and abroad several times. In response to her understanding of the world, she wrote the Dewey Decimal Method abroad instead of the Chinese Diagram Method in China, and made simple changes.

"Number one, philosophical and psychological works, reflections on the abstract nature of the world and reflections on the nature of intelligent life fall into this category. No. 2, Religion and Theocracy, including the scriptures of the Church, the writings of the interpretation of the scriptures, the analysis of the nature of theology, the guidance on the use of theological methods, etc. No. 3: Social works, including legal and administrative books, as well as economic and cultural research results——"

It could have been divided into more different categories, but considering the situation in the world of Seerland, she merged and modified some of the categories. After all, the world is underdeveloped in many academic fields.

"No. IV, Languages, including dictionaries of various languages, and the study of general linguistics. Number Five, Arcane knowledge and basic subjects, including law mathematics, astronomy, naturalism, and spell books. Number six, which does not deal with arcane technologies such as folk medicine, engineering, agriculture, and manufacturing. No. 7, Literature and Art, including literary works and literary theories, appreciation of music, painting, sculpture, etc. ”

Normal people are afraid that they will already be dizzy when they see this. But Xiaowei is a talented mage after all, and she forced herself to keep watching:

"Number eight, military science, the knowledge of the secret warriors is also classified in this category for the time being. No. 9, History and Geography, including world history and the history of countries, maps, geological studies, travelogues, and biographies. Books and documents numbered zero, consulted, typed, and other items that cannot be classified under the above nine categories are placed here. ”

"Each major category is divided into medium categories, and each medium category can be sub-classified, which is also expressed by a number from zero to nine, and vacancies are allowed, up to a total of 1,000 sub-categories. In this way, each book can be represented by a three-digit code. By adding a number to the end of the code, all officially published books can have a unique number. ”

There was a brief silence.

Do you know what you did? Xiaowei asked as calmly as she could.

[A taxonomy?] The girl responded. In fact, she knew very well that the plan made up on the spot was really not perfect. The sub-category didn't have time to think about it at all.

[It covers everything we've learned so far—]

[If it does not cover the entire knowledge system of Gai civilization, classification is meaningless. The girl said gently.

[It's a new system!] Xiaowei looked a little excited, "Do you know what Okad's library is? theoretical theology and theology; the power of the sea of clouds other than divine arts, that is, arcane and mystical rituals; History; Poetry and Drama. Your taxonomy...... Looks better. 】

Of course I knew, the girl thought, that she had noticed that even the book taxonomy in Black Floating City was no better.

It's almost the classification of the "subset of scripture and history...... The details are even more confusing. There are still quite a lot of disorganized books in the library of the floating city, and there is indeed a need for improvement in management.

That's why she came up with such a thing.

Sometimes, the girl waved her hand again and again, and she organized a large amount of information that could be obtained by the catalogue itself. It's a way of building a system. 】

The "system of systems" is an indispensable part of contemporary civilization.

[The system is more important. Do you understand? The principle that classification must cover the entire civilization alone has already ......] Xiaowei was amazed.

"This wisdom belongs to my home world. The girl said proudly.

[You must have been going to the library a lot in the past, right?] Xiaowei asked softly, [Collecting books...... How many? 】

[If you're asking about my university's library, there are nearly a million books there.] 】

[That's more than any library in Erios.] 】

[In my home country, such libraries can be found in every big city. 】

【......】Xiaowei fell into a brief loss of consciousness.

The girl waited for Xiaowei to speak.

Finally, Xiaowei took a deep breath, "You are a human from another world, and there are many things in your world that our world does not have. A taxonomy like this would benefit the whole world a lot. Please. 】

[Please...... Is it? On the contrary, the girl was a little hesitant.