Summary of The One Thing by Gary Keller

  • Post category:Summaries
  • Post last modified:September 18, 2023

Summary: 10 minutes

Book reading time: 3h16

Score: 8/10

Book published in: 2012

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  • Pareto’s law is everywhere.
  • At any moment in time, there is only one thing that will move the needle much more than anything else.
  • Success is about finding that one thing and doing it.

Table of Contents

What The One Thing Is About

The ONE Thing is a book written by Gary Keller. It explains that there is only one thing that will help you get significantly closer to your goal. That thing is the only thing you should be doing. Drop the rest. Success is a matter of focusing on a few things only. The book explores this principle in various situations in life.

The ONE Thing is an interesting book about an interesting principle that ironically, the author failed to respect.

There were many important pieces of information that should have been explored more while simultaneously, many were completely irrelevant.

As a result, the book got me excited, longing for more, and bored almost at the same time.

Quite of an emotional ride!

The ONE Thing is nice because it’s not too long, and to the point, but it lacks clarity.

It’s a good introductory book to organization and self-development.

If you’re someone that lacks focus in your life, I definitely recommend it.

Alternatively, you can read Essentialism.

Enjoy the summary!

Get it on Amazon.

Summary of The One Thing Written by Gary Keller

1. The ONE Thing

Extraordinary results are directly determined by how narrow you can make your focus.

It’s only when light is concentrated that it can melt the iron.

-> go as small as possible.

For your achievement to add up, you need to subtract, not add. You need to be doing fewer things.

When you go small, you stare at one thing only, which is the thing that will bring out the most results.

2. The Domino Effect

One domino can start a chain of events and topple millions of other dominos.

All it took was one thing – the first domino.

Now, what’s interesting is that one domino can topple another domino that is 50% bigger.

Domino Effect | Know Your Meme
This principle is so famous that it became a meme.

-> one thing can create a consequence of much bigger other things.

This domino effect applies to the bigger picture of your life.

You do one right thing, then another one, then another one, and your life changes.

Anyone that has a lot of anything (money, knowledge, skills) acquired it over time.

Over time is key, as this is how success is built.

3. Success Leaves Clues

Proof of “the one thing” is everywhere.

Companies that excel, excel at one thing.

People excelling at one thing specifically started with a passion, that they transformed into a skill, then a profession.

Before we talk about the one thing, we need to see through the lie we have been told about it.

Part 1: The Lies

  1. Everything matters equally -> one thing usually matters much more than the rest.
  2. Multitasking -> unitasking
  3. A disciplined life -> a focused life
  4. Willpower is always on will-call -> use it intelligently
  5. A balanced life -> no good thing comes out of balance
  6. Big is bad -> big is good

These six lies prevent us from being successful by applying the one thing.

We’re going to discuss them now.

4. Everything Matters Equally -> No

In the real world, things are never equal.

The question is: how do you prioritize? How do you do that which you are supposed to do?

First, ditch the to-do list.

Create a success list instead, a list that prioritizes results.

If a list isn’t built around success, it won’t take you there.

To-do lists are long. Success lists are short. They pull you in one direction.

So, how do you make a success list?

With the Pareto principle. The Pareto principle is the idea that 80% of your success comes from 20% of what you do.

-> focus on the 20%, the small things that create big success.

Go extreme: don’t merely do the 20%. Only do the 1% that will make 99% of the success.

image 119
There’s only one thing that will get you where you want to be.

5. Multitasking Works -> No

Multitasking is a productivity lie. It’s neither efficient nor effective.

Furthermore, switching between tasks is costly to the brain.

The brain cannot focus on several things at once.

6. You Need More Discipline -> No

You don’t need more discipline. You just need to apply it better.

What you need is a habit: doing something on a regular basis until you become good.

-> success is about doing the right thing, not about doing everything right.

As long as you are disciplined enough to do the right thing daily, you will succeed.

It takes around 66 days to establish a habit. It is hard at the beginning, easy at the end.

7. Willpower Is Always on Will-Call -> No

Willpower cannot be summoned at will.

The infamous marshmallow experiment showed how kids that had the willpower to wait for the second treat fared much better in life -> willpower to delay gratification is a strong indicator of success.

And yet, it is so hard to practice.

Willpower is like a battery. After you used it (and if you use it too much), you need to recharge.

-> use your willpower accordingly:

  • use your willpower on the important tasks
  • don’t waste it anywhere else
  • do what requires willpower before you run out of willpower (do the most important in the morning)

Things that draw your willpower:

  • New behaviors
  • Filtering distractions
  • Resisting temptations
  • Suppressing emotions
  • Restraining aggression
  • Suppressing impulses
  • Taking tests
  • Trying to impress others
  • Coping with fear
  • Doing something you don’t enjoy
  • Selecting long-term over short-term rewards

8. You Need More Balance -> No

A balanced life is a lie. Nothing is ever balanced. Balance doesn’t exist.

A successful life is driven by purpose, not balance.

Extraordinary results require focused attention and time.

image 120
Prioritize focus over balance.

-> results don’t happen in the “middle”. They happen in the extreme (Nassim Taleb would call it “in the tail”).

Eg: you grow muscles only when you’re making the last rep of the last set -> 2 movements make 99% of the volume of muscles you get.

The problem is that if you pursue the extreme in two activities -> you’ll reach the middle for both of them -> you’ll get long hours, no results, and a loss of time.

Beware of your time. It’s the only thing you really have.

Believing that life is balanced encourages you to do things you shouldn’t which has a negative impact on your life.

The question of balance is actually a question of setting up priorities.

Extraordinary results demand that you set a priority and act on it.

9. Big Is Bad -> No

Big has been linked to bad through folklore (the villain is often a big bad guy), but these two things are inherently unrelated.

If you fear big success, you’ll either avoid it or sabotage your efforts to achieve it.

We are afraid of big for no reason, and this fear paralyzes us. It prevents us from going further, past our limits (which are imaginary most of the time).

Thinking big is essential to extraordinary results.

If: thoughts -> actions -> success

Then: big thoughts -> big actions -> big success

Don’t fear big.

Fear mediocrity instead.

The best way to think big is to double down everywhere in your life.

Don’t aim at making 20k. Aim at making 40k.

Don’t aim at losing 10kg. Aim at losing 20kg instead.

image 121
Go big.

Part 2: The Truth

When the author was trying to be successful, he did everything by the book. He talked, dressed, and acted like an arrogant successful person. He slept little, only worked, and was very busy.

That got him success, but he also became sick and had to rest.

When he was tired of this lifestyle which wasn’t “who he was”, he went back to being himself and practiced the opposite he had done. Instead of doing more, he did less.

He became much more successful as a result.

-> success is not created by all that we do, but only a handful of things we do.

10. The Focusing Question

Andrew Carnegie (second richest man in the world at some point) said that diversification is a bad strategy to achieve success.

Embed from Getty Images

He said instead to put all of your eggs in the same basket and relentlessly focus on it.

The question is: which basket should you choose?

The answer to this question is not interesting.

What’s interesting is an alternative question to this question.

-> the real question you should ask is the Focusing Question:

What’s the one thing I can do such that by doing it everything else will be easier or unnecessary?

The answer to this question is the one thing you should absolutely focus on.

It’s your basket with all of your eggs.

11. The Success Habit

You should make a habit out of asking yourself the Focusing Question.

It’s the best tool at your disposal to have an impact big enough on your life.

This question works also in specific areas of your life.


  • What’s the one thing you can do to improve your relationships?
  • What’s the one thing you can do to improve your health?
  • etc

In order to start asking this question you should

  1. Understand and believe that there really is one thing you need to do to drastically improve your performance.
  2. Use it. Ask yourself the question each day.
  3. Make it a habit.
  4. Remind yourself to use it.
  5. Talk about it with other people.

12. The Path to Great Answers

Great questions -> great answers.

If you seek great answers, you should ask great questions.

Great questions are big and specific questions that expand your world.


  • “What can I do to double sales in the next 6 months” is a great question (big and specific).
  • “What can I do to increase sales?” is not a great question (broad and small).

Answers to questions come in three categories.

  1. Doable: it’s something easy you can do now.
  2. Stretch: it’s something you could do, but you’d need to research first how to do it.
  3. Possibility: it’s something that is possible to do, but you have no idea how you’d do it.

You should go for option 3.

If you already know the answer to a question, then the answer is not big enough and you should seek a better answer.

When looking for answers, look at the work of people that already tried to do what you did, then build on their answers (which can be failures, or successes).

-> keep in mind that a difficult answer will lead to great success, and the other way around.

Don’t seek small, easy answers. Seek the big ones!

image 118
Seek the biggest answer.

Part 3: Extraordinary Results

Extraordinary results happen when purpose, priority, and productivity are bound together.

Purpose + priority -> productivity.

Purpose and priority are seldom talked about, but exist behind all healthy productivity.

13. Live With a Purpose

There are five factors that contribute to our happiness.

  • positive emotion and pleasure
  • achievement
  • relationships
  • engagement
  • meaning

The last two are the most important.

Happiness is what you get when you go after a purpose. If the purpose is bottomless (like money, because you can always have more), then you will always be seeking more, and never be happy.

Which is why you should go after definite purposes.

Purpose is your best source of strength.

You’ll move forward in life if you know what you want and take action to get it.

Ask yourself the one question “what’s the one thing I can do to get closer to my purpose and that would simplify everything else“, and do that thing.

That’s how you make you’re headed in the right direction.

14. Live by Priority

Live with purpose and you will know where you want to go.

Live with priority and you will know how to get there.

-> purpose without priority is useless.

Priority was a singular word originally. It was only pluralized in the 20th century.

In a way, “priorities” is an oxymoron. You can only have one priority.

So, since the pluralization of “priority”, we added the adjectives “main, top, highest” etc to priority, which is dumb.

Why do we have priorities?

Because “now” is the only moment we have. The past or the future are inaccessible. Always.

Priorities help you sort out what you should do now.

Powerful moment + powerful priority = success

Based on your goal this year/month/week/day, what’s the one thing you can do so you are on track to achieve it?

15. Live for Productivity

Life isn’t about wondering if we’ll do something or not.

It’s about wondering what we will do.

Successful people do the most of what they must do.

-> productivity is about taking (the right) action, not doing things right.

To make sure you have time for your one thing, you must block your time.

It means blocking all the time you need to accomplish your one thing.

And not stopping until you have accomplished it.

To do so, you’re best off isolating yourself from any possible distractions – physically, mentally, and digitally.

16. The Three Commitments

Extraordinary results demand three commitments.

  1. A mastery mindset to embrace extraordinary efforts you must make to become a master.
  2. Seek the best way of doing things.
  3. Achieve your one thing.

Mastery is giving the best you have to become the best you can be at your most important work.

Mastery happens over time, usually after 10 000 hours, which is roughly 3h/day, 365 days/year, for 10 years.

Most of us when we do something, are entrepreneurial in our mindset.

We do it, we try, then when we reach a plateau and we jump onto the next thing -> it’s bad.

You should abandon this entrepreneurial mindset and replace it with a purpose mindset, where the thing you want to do is definite and where you will have to acquire new skills to do it.

17. The Four Thieves

The following four practices will prevent you from being productive.

1. The Inability to Say No

1 yes must be defended against 1000 no’s.

To get something (results, success), you must give up something else.

Knowing what you must give up is part of knowing what you want.

So, if you want to say “yes” to one thing, you’ll have to say “no” to many more.

2. Fear of Chaos

You won’t be able to avoid chaos.

Get used to it and get over it.

Doing your one thing is more important anyway.

3. Poor Health Habits

“If you don’t take care of your body, where will you live?”

Poor health habits lead to energy mismanagement, which steals your productivity.

Good health habits include

  • A healthy diet
  • Exercise
  • Enough sleep
  • Good relationships

The daily energy plan (according to the author):

  1. Meditate and pray for spiritual energy.
  2. Eat right, exercise, and sleep sufficiently for physical energy.
  3. Hug, kiss, and laugh with loved ones for emotional energy.
  4. Set goals, plan, and calendar for mental energy.
  5. Time-block your one thing for business energy.

4. An Unsupportive Environment

If the people surrounding you aren’t supportive, it will be very difficult to achieve what you want to achieve.

For example, if the people around you are obese, you have 57% more chances to become obese yourself.

-> other people tend to set the standards for what is appropriate for us.

Both your friends’ success and failure will influence your own -> hang out with the right people!

Furthermore, the actual place where you stand impacts your performance.

-> if your environment is full of distractions, you’ll never achieve anything.
-> if your environment is bringing you down, you’ll never be happy.

18. The Journey

Any journey always starts with a single step: the one thing.

Doing big things is that simple.

You need to start small, and do the thing that will most likely make you move forward and bring you closer to your big goal.

There is a story that says that human beings have two wolves inside, constantly fighting each other. One wolf is fear, the other is faith.

The one that wins is the one you feed.

There is, besides success, another reason to wake up and do your one thing and succeed.

It’s the absence of regrets.

To quote Mark Twain,

Twenty years from now you will be more disappointed by the things that you didn’t do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.

It’s what you don’t do that generates the greatest regrets.

And regrets are things you can never change.

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