#1 New York Times bestseller, and a long-term bestseller worldwide.
It gave hope and empathy to readers in their 40s and 50s.
How a Harvard professor can make the most of the latter half of his life.

This book began on a late-night plane ride.
The author hears a man of great worldly accomplishments confess to his wife, "I would rather be dead."
His abilities had declined, life had become frustrating and dissatisfying, and he felt as if no one cared about him the way they used to.


The author began to research whether a period of decline like that of the man on the plane might be his future, and what he could do to prevent that fate.
He delved deeply into diverse fields, from his own specialty, social science, to adjacent disciplines like brain science, philosophy, theology, and history. He also delved into the study of people striving to become the best, interviewing hundreds of leaders.

As a result, those who strive to be the best inevitably face a period of decline, and they come to realize that the success they have achieved is becoming increasingly dissatisfying and they feel a lack in their interpersonal relationships.
Studies have shown that people who pursue power and achievement at work are more unhappy in retirement than those who don't.
The more attached we are to the success and talents of our youth, the sooner we notice our own decline and the more painful it is.


Professional skills peak around the 20th year of employment and then decline steeply.
Happiness gradually decreases and reaches its lowest point in one's 50s.
Those who were once successful feel the fall more acutely and choose to work harder to not lose sight of their achievements.
But the author says that this behavior ultimately only leaves behind anger and frustration.


The author achieved great success, leading a world-class think tank. At the age of 51, he made a major change in his career and attitude toward life to achieve success in the second half of his life, and is now living a fulfilling and happy life.
The author says in this book that because strengths before and after 50 are different, we need to discover new strengths as we age and get on a new second life curve.
It also deals with how to accept death naturally and become friendly with our inevitable fate, and it reveals that the secret to enduring and enjoying loneliness and falling is to connect our roots to others, just as the roots of the trees in a grove of aspen trees are connected to each other.


This book teaches people how to transform professional and social decline into opportunities for growth and transcendence, rather than regret and anger. It helps people in the second half of life find new purpose and meaning in life and make the remaining years a time of happiness and success.

“There is no place that wants you anymore.
“That’s a ridiculous idea.”
That day, I was sitting on a plane departing from Los Angeles late at night.
The plane landed in Washington D.C.
As I was flying towards C, I heard an angry voice from an older woman in the seat behind me.
The cabin was dark and quiet.
Most of the passengers were sleeping or watching movies.
A man, presumed to be the woman's husband, muttered something unintelligible, and then his wife said:
“Oh, please stop saying you’d rather be dead.” Before I knew it, I was completely absorbed in their conversation.
I didn't intend to eavesdrop on it, but it happened without me knowing.
I listened to their conversation half out of interest as a human being and half out of professional interest as a social scientist.
I pictured my husband sitting in the backseat.
I imagined that he might be a person who worked hard all his life without a name.

---From "Entering_A Man I Met on a Night Plane"

Most people think that the day will come when they are too old to perform as well as they used to, and that will come much later.
A look at some interesting survey results provides a glimpse into this thinking.
For example, in a 2009 survey, when asked "At what age do you consider old age?" the largest number of American respondents answered 85.
In other words, the "average American" who lives to age 79 will die six years before reaching old age.

---From "Chapter 1: The Party of Life Doesn't Go On"

The biggest difference between the two was how they managed their own lives.
That is, there was a difference in how they accepted the decline that came in middle age as innovators.
Darwin was depressed and discouraged when he hit the wall.
His life ended in sorrow.
Like most people, he either found or failed to find the second curve.
In other words, in his later years he experienced only decline.
Meanwhile, when Bach realized that his fluid intelligence curve was tilting, he jumped on the crystallized intelligence curve with all his might and didn't look back.
As an innovator, he chose to become a leader when he was left behind.
According to reports, he died loved and respected, feeling fulfilled and happy.
Even though it wasn't as famous as it was in its prime.

---From Chapter 2: How to Overcome Aging

Like most strivers, you have probably been striving for decades to achieve success in the worldly sense.
And now I'm asking you to go against that instinct.
But once you embark on this journey, you will realize that much of your life has been about building an 'image' of yourself and others that shows you how successful and special you are.
And some of these are material spoils, 'positional goods' that show you are very important in the world.
It could be a house, a car, or a boat.
But don't feel bad if these things don't matter to you or if your success doesn't depend on money.
Your loot might be social media followers, famous friends, or living in a popular neighborhood.
What I'm trying to say is that the symbols of specialness surround you like so many barnacles, with a hard outer shell.
Not only do these things not bring you true satisfaction, they also weigh you down so much that it's difficult to jump to the next curve.
A lot of them need to be stripped down.
But what should we take away?
---From Chapter 3, “Escape from the Addiction to Success That Leads to Unhappiness”

Satisfaction is what you have divided by what you want.
Do you see the difference between this and the equations we've seen before? All evolutionary and biological equations focus us on the molecule—what you "have."
If you are dissatisfied with your life, chances are you have been for a long time.
This is because the denominator of the satisfaction equation, ‘what you want,’ was not taken into consideration.
If you simply increase your possessions without properly understanding what you want, your demands will increase rapidly and run wild.
The higher you climb the ladder of success, the more likely it is that your satisfaction will diminish.
Because what you want always surpasses what you have.
And when that happens, your satisfaction level drops.

---From Chapter 4, The Relationship Between Bucket Lists and Happiness

A few years ago, I had lunch with an old friend of mine, who was about my age and now works as a CEO at a company.
I told him about the research studies in this book.
I talked about the inevitable decline of fluid intelligence and how difficult that is for many successful people to deal with.
Then he said, “I don’t worry about that.”
“How could I not?” I asked.
“I will not decline.
“You just keep running harder and harder until the wheels fall off.”
In other words, it means that you will work, work, work, and work until you collapse.
So what I was saying was that there was no need for a second curve or anything like that.

---From Chapter 5: Thinking Concretely About Death

As I later learned, the ash tree was not as solitary a creature as I had thought.
According to a friend who knows much more about trees than I do, each 'individual' tree is part of a huge root system.
In fact, the fir tree is arguably the largest living organism on Earth.
A grove of aspen trees called "Pando" in Utah covers approximately 430,000 square meters and has a root system that weighs up to 6 million kilograms.
The single ash tree I was looking at was actually not all that there was, but one of the trees that grew out of a huge root system.
That is, it was one of countless trees that emerged from one identical living organism.

---From Chapter 6, "Grow Your Own Forest of Zelkova"

It is a mistake to view weaknesses only in a negative light.
Any human being can have weaknesses, and these weaknesses can cause inconvenience and loss.
But it is also an opportunity.
An opportunity to connect more deeply with others, discover divinity in suffering, and pioneer new realms of growth and success.
Don't try to hide your weaknesses, nor resist them.

---From Chapter 8, “Turn Your Weaknesses into Strengths”