Library

At Sham Shui Po, outside the Po On Road Municipal Services Building, a yellow taxi slowly pulled into the parking area.

"Here we are, 110 bucks. This is the nearest large library around here. I heard it opened just a few years ago," the driver, a short and chubby middle-aged man, said as he turned slightly in his seat and pointed out the window at the building, addressing Yang Chu, who was sitting in the back.

"Thank you!"

Yang Chu glanced at the building outside the window, took out a 100-dollar bill and a 10-dollar bill from his wallet, handed them to the driver, and got out of the taxi.

He made his way into the municipal building, took the elevator to the second floor, and arrived at his destination: the Po On Road Public Library in Sham Shui Po.

Yang Chu intended to thoroughly browse through some books to see if he could find a solution to his problem.

He chose not to seek help from medical or other professionals. Hong Kong is a capitalist society, and with less than a thousand Hong Kong dollars left in his pocket, he didn't even have the qualifications to book an appointment at some of the high-end clinics or with specialized medical professionals.

Even if he could reach some suitable institutions or professionals, whether they could solve his sleep problem was another matter. What was certain, however, was that he would quickly become a subject of research and experimentation.

Of course, in the face of life and death, there's little that can't be compromised.

Still, until he had no other options, Yang Chu wouldn't easily let others take control of his fate.

He wasn't even sure why he was thinking this way—

His memories from his past life had many gaps. The life he remembered was blurred and fragmented.

Fortunately, his ability to think and reason logically, and much of the knowledge he had learned, remained intact.

When faced with these problems, his mind could combine his current situation to make judgments and decisions.

Whether these decisions were correct or effective, or if they could solve his current problems, was something he couldn't dwell on much further.

These somewhat scattered thoughts were just fleeting moments that passed through Yang Chu's mind while he quietly sat in the back of the taxi earlier.

The Po On Road Public Library was clean and bright, with a pleasant atmosphere.

The library wasn't very large, with about four or five employees wearing name badges working there.

Once inside, Yang Chu's eyes quickly scanned the sections on the bookshelves, and he soon found the biology and medical sections.

There weren't too many books—about four long rows of shelves—and they ranged from new to old, indicating that aside from purchases, some books were likely donated by the public.

Most of the books were in traditional Chinese, with a few in simplified Chinese scattered throughout. A large portion was in English, but Yang Chu didn't find this too difficult.

Quickly scanning the shelves, Yang Chu soon stopped at one of them and pulled out a book.

The title was *The Most Familiar Stranger*, with a subtitle about self-awareness and discovering potential.

Yang Chu briefly glanced through the table of contents and flipped through a few pages. Feeling it might be useful, he set it aside on the nearest shelf and continued searching for other books.

He picked out two more books, *The Efficient Rest Method* and *The Compressed Sleep Method*. After skimming the tables of contents, he sensed they might contain some of the information he needed and placed them on the nearby shelf, continuing his search.

"Having trouble sleeping?"

As Yang Chu carefully selected books, a gentle voice suddenly spoke beside him.

He turned to see a handsome young man wearing earphones and pushing a cart loaded with books passing by. He appeared to be a library staff member.

"Yes, my mind won't quiet down, and I can't sleep," Yang Chu casually responded.

"I often have trouble sleeping at night too."

With a shy yet friendly smile, the young man placed a few books on a nearby shelf and said, "If you want to try to get a good night's sleep, you might want to check this out—"

With that, he handed Yang Chu an old book from his cart.

Yang Chu took the book and glanced at the title, *Why We Sleep*. It looked like it might be helpful, so he nodded slightly. "Thanks!"

"You're welcome!"

The young man smiled, continued pushing his cart, and moved on to other shelves.

Yang Chu casually glanced at the books on the young man's cart. Titles like *Why We Are Here*, *The Weaknesses of Human Nature*, and *Personality Tests* caught his eye.

After the young man left, Yang Chu didn't pay much attention and continued browsing through the bookshelves.

He didn't start reading any book immediately but continued to search for the ones he wanted, placing them in front of him.

His body was still standing and moving, and besides controlling the internal systems of his body, his mind also had to control his motor functions. Without a subconscious mind managing his body, if he became too engrossed in reading, his body would suddenly collapse rather than remain standing.

For longer periods of reading, he needed to minimize his brain's focus on other tasks.

He picked out titles such as *Save Your Sleep*, *Awaken the Sleeping Brain*, *Efficient Brain Functioning*, *The Second Brain*, *Brain Repair Techniques*, *An Explanation of Consciousness*, *The Neural Atlas*, and *Introduction to Brain Science*...

Yang Chu selected over ten books from the shelves, both new and old. As long as he thought they might be useful or spark some ideas, he kept them.

He then carried the large stack of books to a reading table not far from the shelves.

Naturally, sitting down with dozens of books attracted the attention of the surrounding patrons.

However, Yang Chu ignored the curious glances. Once seated, he adjusted his posture and began flipping through the books.

Yang Chu first wanted to understand why humans need to sleep.

He seemed to have some memories related to this, but they were fragmented, likely from "news headlines" and "public accounts," and were neither accurate nor clear. He had forgotten much of it.

Moreover, these discussions tended to focus not on why people sleep but on the harmful effects of not sleeping enough and the dangers of staying up late on the body.

Drowsiness, fatigue, inability to concentrate, forgetfulness, blank mind when thinking, slowed reactions, emotional instability, increased risk of illness and cancer, accelerated aging, general discomfort, and so on.

Yang Chu was aware of these severe consequences of sleep deprivation, but they weren't the answers he sought.

Flipping through several books, Yang Chu slowly found some explanations.

These could be considered hypotheses and conjectures.

The first theory was that sleep is for conserving energy.

When animals were first evolving, food was scarce. Sleep was meant to reduce the basal metabolic rate, allowing energy to be conserved and restoring the energy lost during the day, similar to how some animals hibernate.

But this theory seems inaccurate now. As evolution progressed, food intake for humans ceased to be a problem.

If sleep were just for conserving energy, then with sufficient energy intake, humans wouldn't need to sleep.

So, besides conserving energy, sleep must have other purposes.

The second theory suggested that sleep is for memory.

Sleep helps repair neural tissues and plays a role in the protection and consolidation of memory.

This theory makes some sense and is somewhat accepted, but it still seems incomplete.

The third theory proposed that sleep efficiently clears metabolic waste from the brain, restoring vitality.

Most metabolic waste in the brain is released from brain cells into the interstitial space, where it is flushed away by cerebrospinal fluid. Cerebrospinal fluid provides nutrients to the brain and helps remove waste. It flows along the spaces around the arteries into the brain, exchanges with interstitial fluid, carries the metabolic waste to the spaces around veins, and then removes it from the brain.

During sleep, the interstitial space in the brain is larger than when awake, which means that cerebrospinal fluid can more easily enter the brain and exchange with interstitial fluid. Sleep might prevent the accumulation of toxic metabolic waste, thereby protecting brain cells.

It's like the brain taking a bath with cerebrospinal fluid during sleep, washing away accumulated metabolic waste. Sleep's function could be described as a genuine "detox."

Yang Chu found this theory somewhat reasonable.

It might not be entirely accurate, but it seems to be part of the reason why sleep is necessary.

Additionally, some say sleep is related to immunity and produces specific secretory proteins with antibacterial properties.

People often feel tired and sleepy when sick, but this increased need for sleep is due to immune and nervous systems releasing signaling molecules, not the infection itself.

Other theories suggest that sleep initially served a primitive function during early evolution. As for what that function was, there is no definitive answer. Over time, sleep acquired more functions as evolution continued.

Some theories propose that sleep is necessary to optimize brain function, is linked to the Earth's day-night cycle, or is a way to hide from predators at night.

From the many books, Yang Chu didn't find a clear and definitive answer.

He didn't know if it was because there were too few books in this library, or if human understanding of biology and the self hadn't yet reached this point.

However, Yang Chu felt he had gained some insights.

Among the books he read, he also came across some intriguing ideas.

One was that we aren't truly sleeping; "awakening" is what we should be striving for.

Most lower-level organisms neither sleep nor awaken; they exist in a state of low perception and low energy.

For example, all plants, bacteria, viruses, plankton, and even insects. Their numbers far exceed the combined total of humans and all animals. They move mechanically day after day and have never awakened. Humans, however, have awakened from lower life forms, gaining wisdom and control over their lives.

Through these books, Yang Chu also learned many things he hadn't known beforeabout sleep:

In mammals and birds, sleep can be divided into two main stages by analyzing eye movements—Rapid Eye Movement (REM) sleep and Non-Rapid Eye Movement (NREM) sleep.

REM sleep is characterized by rapid eye movements, high-frequency and low-amplitude brain waves, and reduced muscle activity. Most dreams occur during this stage.

NREM sleep takes up about 75-80% of an adult's sleep time. Dreams are relatively less common in NREM sleep. It consists of four stages: the first two are light sleep, while the third and fourth are deep sleep. Each stage has distinct characteristics.

There are also many animals whose sleep duration is shorter than that of humans. For example, elephants only need about two hours of sleep each day.

Some marine mammals, such as whales and dolphins, don't need their entire brain to be asleep at once. Their left and right brains can rest alternately, so at any given time, half of their brain is awake to handle daily tasks. There are also small animals that sleep very little to avoid being caught by predators.

Apart from the books on sleep, Yang Chu also found some interesting points about "subconscious" in other books.

One idea was to cultivate a self-controlled subconscious.

For example, if an ordinary person suddenly sees something flying towards them or faces a direct attack, their subconscious instinct would be to close their eyes.

However, a trained boxer or other martial artist, through long-term practice, has fully controlled this subconscious instinct. When facing an attack, instead of closing their eyes, they would keep them open to see the attack's trajectory and make an evasive move accordingly.

"How's it going? You've been sitting here for almost a day. Have you found a solution for your sleep problem?"

A gentle voice interrupted Yang Chu's thoughts again.

Looking up, he saw the same young man from the library standing beside his table, watching him.

It was only then that Yang Chu noticed it was already dark outside; evening had arrived.

Except for this young man in front of him, everyone else had already left the library.

"I've found some insights, but I'll have to test them to see if they work."

Yang Chu understood that the young man was hinting that the library was about to close. He had gained a lot this afternoon, and surprisingly, he managed to skim through and grasp the essence of the books he had selected.

Closing the book, he stood up from the table.

However, probably due to sitting for too long, even though he had kept his heart pumping and blood circulating, his legs were still slightly numb, causing him to stumble to the side as he got up.

"Careful!"

The young man, quick-eyed and swift, caught Yang Chu and smiled, "Looks like you've been sitting too long without moving. You should stand up and stretch a bit..."

"Thanks, I'm fine!"

Yang Chu slightly sped up his heart rate, increasing the blood circulation in his body. In just about ten seconds, the numbness in his lower body was gone, and he no longer needed support.

"You recover quickly!"

The young man was momentarily surprised by how quickly Yang Chu regained his stability.

"I just sat a bit too long," Yang Chu replied with a smile. Then he asked, "By the way, could you tell me where the restroom is?"

As he spoke, Yang Chu glanced at the young man's rectangular name tag on his chest. It was a badge with several English letters—Xuxi.

"My name is Xu Xi," the young man said, noticing Yang Chu's gaze. He gave a shy smile and pointed to the other side of the library, "Just turn around that corner."