After engaging in a silent dialogue with more than 3,000 corpses at the autopsy table, South Korea’s leading forensic pathologist, Ryu Seong-ho, transforms the stark truths revealed beneath the cold scalpel into a warm yet sobering lesson about life.
As you open this book, you will hear the silent cries of the human body’s organs, come to understand the harsh logic behind disease and accidents, and gain a “survival guide” from the very depths of death—
a guide on how to honor and respect your body, how to steer clear of danger, and how to live with clarity and resilience within the finite span of time that is yours.
This is not a book about death; it is a deeply heartfelt reminder of the preciousness of life.
For only those who truly understand death can truly grasp how to live well.

South Korea’s leading forensic medicine expert, Professor Ryu Seong-ho of Seoul National University College of Medicine, still spends every week in the autopsy room, facing human remains. Since performing his first autopsy in 1999, he has conducted more than 3,000 autopsies, giving him a deeper understanding of how humans die than anyone else. Drawing on the vast array of death cases he has encountered over 27 years, this book delves into the inner organs of the human body and explains, in both a professional yet accessible manner, potential ways to delay death caused by disease or accident. Through shocking autopsy cases from his own experience, the book provides a detailed analysis of the major organs and life-threatening diseases while offering practical advice on “how to stay away from death and live a healthy life.”

I am a doctor who can only meet people after the flame of life has been extinguished—a forensic pathologist. Diagnosing and prescribing for the living is the responsibility of other excellent physicians, while I can only encounter the deceased at the final scene of their lives. Each time, I silently repeat in my heart:
“If only I could have met this person while they were still alive…”
Since performing my first autopsy in 1999, I have now completed more than 3,000 autopsies. As a result, I know better than anyone else how people die. I hope that this knowledge does not merely stop at interpreting death; rather, paradoxically, it leads to profound insights about how we should live.

Page 7, “Preface: A Doctor Facing Death—A Record for Protecting Precious Lives”
As I opened his chest cavity on the autopsy table and held his heart in my hands, I couldn’t help but be shocked. At his age, the heart should typically weigh around 320 grams, but his heart was abnormally enlarged, and when I removed it, I could feel its heavy weight. It clearly exceeded 500 grams. I carefully sliced the left coronary artery at intervals of about 0.3 centimeters to examine it and found that the inner wall of the blood vessel was completely blocked by hard atherosclerotic plaques. The muscle of the anterior wall of the left ventricle had turned white, and some areas showed red necrosis. The cause of death was acute myocardial infarction.

Page 16, “The Most Common Case Forensic Pathologists Encounter on the Autopsy Table—The Heart”
Many people believe that young people do not need to worry about heart diseases such as myocardial infarction, but in my autopsy experience, there have been surprisingly many cases where individuals in their thirties suffered a heart attack. There was once a news report about a delivery driver who suddenly collapsed and died while working. It was said that he felt chest pain while making deliveries, but because he was busy with work, he thought a short rest would suffice, so he persevered and continued working, only to collapse in his vehicle. The autopsy revealed that about three-quarters of his blood vessels were indeed blocked. Cases like this—where someone appears to be living a normal life but suddenly dies—are most commonly caused by cardiovascular diseases.

Page 31, “The Most Common Case Forensic Pathologists Encounter on the Autopsy Table—The Heart”
The brain is not a simple organ. It cannot be reduced to a mere “command center” that sends signals to the body or a “computer” that regulates thought and emotion. The brain is a unique universe that contains an individual’s personality, memories, desires, fears, love, and other intangible aspects of their inner world.
As a forensic pathologist, I observe the brains of the deceased every day. Although life has ended, the brain still preserves the full trajectory of their lives. In some brains, there are traces of accidents; in others, shadows of disease; and in still others, fragments left behind by violence inflicted by others.
Observing the brain is not just about recording pathological changes; it is also about tracing the journey an individual took up to the very end. Therefore, the brain is not merely an organ. It is the deepest story of a person—a final language that endures even beyond death.

Page 61, “The Deadly Organ That Ends Everything in an Instant—The Brain”
Pneumonia is an extremely common lung disease and ranks third among the leading causes of death in our country. While it may initially bring to mind severe coughing or hemoptysis, pneumonia often progresses quietly, manifesting as general weakness. In a healthy person, oxygen saturation in the arteries should be close to 100%, but when pneumonia sets in, oxygen saturation drops, gradually leading to suffocation. In other words, patients grow weaker and weaker due to breathing difficulties and eventually succumb to respiratory failure.
During an autopsy, the signs of pneumonia are very obvious and easily visible to the naked eye. A normal lung is like a sponge, filled with tiny air-filled spaces that allow air to circulate. But in a lung affected by pneumonia, these countless spaces are filled with white blood cells, debris, pus, and other substances, and the bronchi are clogged with yellow, mucus-like inflammatory secretions. If an X-ray is taken during the patient’s lifetime, the lungs will appear hazy, like frosted glass.

Page 71, “From Flu to Pneumonia: Silent Consumption That Leads to Death—The Lungs”
When you touch the brain, it feels as soft and elastic as tender tofu. Once it suffers a contusion, it swells, making it an extremely fragile tissue that is easily damaged. The brain is enclosed by three layers of meninges and the skull, leaving very little space, so even if bleeding occurs not in the brain itself but around it, it can still compress the brain. Less than 200 milliliters of bleeding is enough to compress the brain and cause death.
The same applies to the heart. The heart relies on electrical conduction, and a contusion is like a severed wire. Therefore, in a car accident where the chest slams violently into the steering wheel, causing a contusion to the heart, death can often occur directly as a result.

Page 177, “The Key to the Survival of the Entire Body—Blood”

What is the most common type of autopsy case that forensic pathologists encounter? Of course, autopsies are sometimes performed to investigate the circumstances of crimes such as homicide, but in our country, the leading cause of death is undoubtedly “cancer.” In the past, deaths caused by drunk driving were also frequent, but they have decreased significantly today. Thanks to good public safety, the homicide mortality rate is about 0.6 per 100,000 people. However, among the approximately 300,000 deaths each year, 80,000 to 90,000—about one-third—die from cancer.
In addition, statistics show that 49% of the population in our country will develop cancer at least once before they die. This means there is a high probability that we ourselves, or our family members and close friends, may experience cancer at some point in the future.

Page 217, “Most Koreans Die Because of This—Cancer”
After being contacted by the police, firefighters arrived and opened Mr. B’s door. The house was filled with bottles of alcohol, and maggots wriggled on the floor, as if time had stood still. The autopsy of the decomposed body revealed chronic alcoholic liver disease and cirrhosis. Even accounting for decomposition, the blood alcohol concentration was far above 0.15%. It seemed that he had been drinking alone right up until his death.
In recent times, such solitary deaths have become increasingly common and are frequently seen in autopsies. In particular, they are more prevalent among men aged 50 to 60, but recently, there has also been a rise in middle-aged women who drink alone, leading to an increase in the number of decomposed bodies of middle-aged women. What is even more terrifying than the physical decay of the body is a life destroyed by loneliness and alcohol combined.

Page 230, “An Extreme Medical Perspective on Everything About Alcohol—Alcohol”
What happens if steroids are artificially injected into the body, in addition to the hormones naturally secreted by the body? Normally, testosterone is produced by the testes, but if steroids are already injected into the body, the body stops producing testosterone. This can lead to testicular atrophy, erectile dysfunction, azoospermia, and a decline in sexual desire. If women artificially inject testosterone, their voices become deeper, and their menstrual cycles become irregular or stop altogether. Both men and women may experience hair loss.
Once steroid injections begin, the demand for them tends to increase continuously. As a result, not only does hormonal balance get disrupted, but the overall balance of the entire body, including the cardiovascular system, is also thrown off.

Pages 290–291, “Even a Single Use Is Dangerous—Steroids”

Ryu Sung-ho
Currently a professor in the Department of Forensic Medicine at the Seoul National University College of Medicine, Ryu also serves as a commissioned forensic pathologist at the National Institute of Scientific Investigation. After graduating from the Seoul National University College of Medicine, he completed his internship and residency at Seoul National University Hospital and obtained certification as a specialist in pathology. For 27 years, he has dedicated himself to forensic medicine—a field he regards as both his vocation and destiny—performing more than 3,000 autopsies. As one of South Korea’s leading forensic experts, he is responsible for autopsies and consultations on major cases and crime-related investigations.
Ryu has engaged with the public as a forensic medicine expert on various TV programs, including SBS’s “Unanswered Questions,” tvN’s “You Quiz on the Block,” KBS’s “Smoking Gun,” and MBC’s “Star Lecturer.” On his popular YouTube channel, “Ryu Sung-ho’s Demon Talk,” he shares insights on how to lead a healthy and happy life, earning the admiration of hundreds of thousands of subscribers.
This book features a specially curated selection of content from “Ryu Sung-ho’s Demon Talk”—highly acclaimed segments known as “precious lectures” that explore the human body and disease. In addition, it includes behind-the-scenes stories about autopsies that could not be fully covered in the videos, along with more in-depth and specialized analyses.
As he often recalls and shares: “For the precious lives that shine on this beautiful Earth,” he wrote this book with the hope that no more deaths will be marked by injustice or regret and that everyone can live a healthy life.
His previous works include “Forensic Pathologist Ryu Sung-ho’s Last-Word Notes” and “I Visit Corpses Every Week.”

Prologue
A doctor facing death records his efforts to protect precious lives.

Part One
I’m Curious About Your Organs
The Most Common Case Forensic Doctors Encounter on the Autopsy Table: The Heart
The Final Fate of Clogged or Ruptured Blood Vessels: The Vessels
The Deadly Organ That Ends Everything in an Instant: The Brain
From Flu to Pneumonia: Silent Consumption That Leads to Death: The Lungs
The Decisive Clue Left by the Deceased: The Stomach
The Danger Signals Emitted by the Digestive Tract: The Small Intestine
The Ultimate Barrier in the Abdominal Cavity: The Large Intestine
The Betrayal of a Silent Organ: The Liver
The First Line of Defense Against Invading Bacteria: The Spleen
The Deadly Blow from a Hidden Place: The Gallbladder
Why It’s Already Too Late the Moment You Learn About It: The Pancreas
The Factor That Determines Survival Throughout the Entire Body: The Blood
The Unique Blueprint Engraved in Everyone’s Body: DNA

Part Two
Tell You How to Avoid Dying as Much as Possible
Most Koreans Die From This: Cancer
Everything About Alcohol From an Extreme Medical Perspective: Alcohol
The Most Effective Preventive Prescription for Everyone Today: Cigarettes
When It’s Too Hot or Too Cold, Our Bodies Collapse: Temperature
Even a Single Use Is Dangerous: Steroids
Drugs That Cause Both Physical and Mental Collapse: Diet Pills