The One Thing Book Summary


Hi Success Titan reader, I’m Sal Damiata, and that’s the book summary of “The One Thing,” written by Gary Keller. 

Why this Book?

Are you overwhelmed by massive amounts of distractions like social media apps, text messages, and other things that keep you away from focusing on what you should do? If that sounds like your typical day, keep reading.


The One Thing is a book that is aimed at proving the point that focussing one essential thing is much better than trying to do everything at once, both for your productivity and happiness levels. Anyway, is it really true that focussing is the real key to that? Let’s discover it together.

Who’s it for? 

  • People that have a hard time to focus and keep up with their projects;
  • Everybody who has a lot of things going one but really none of them getting successful;
  • Professionals or entrepreneurs that work with strict deadlines.

What You’ll Learn from it

  • How to remove unnecessary things from your life and get your things done;
  • Helpful strategies to overcome energy depletion and focus dispersion;
  • How willpower works, how to manage it, and when to exercise it.

In a Nutshell

  • Generally, the most professionally successful people on the planet focussed all their energies on one activity, one skill or project until they became successful. If you try to become good at everything, you’re most likely to be average in all those things.

3 Sentence Summary

  • Most of the successful people in the world achieved success because they managed to focus on one thing and become masters at it instead of trying to become good at many things.
  • Use your willpower wisely as the more you engage it, the more it gets depleted. Preferably do the most important activities in the morning when you are fresh and leave the less important ones for the rest of the day.
  • Use the 80/20 principle to find out your one thing, block the time in your calendar when you have to do your one thing and give yourself less time to accomplish your most important task so that you’ll make more efficient use of it.

Big Ideas

Those are the most relevant ideas expressed in the book that we’ll explore together.

  1. Start Small and Go Big
  2. The One Thing
  3. Manage Your Willpower
  4. The Success List & Thinking Big
  5. Use Those Productivity Tips

Time to learn more about them now!

Big Idea #1: Start Small and Go Big

Our life is like a domino game. If we want to make big dominoes fall, we have to make the smallest ones fall first. In fact, if you ever played with such a game, you’ve probably seen how moving one little domino piece can cause a bigger piece to fall. 

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The smaller piece, according to scientific calculations, can make a piece 1.5 times bigger than it falls when hit.

Do this exercise, and by knowing where you want to get and by starting from today, you will create a domino effect that will eventually bring you to your 10-year goal and make this biggest domino fall like a little one. 

This will create vertical coherence and the domino effect, as well. That’s why the author suggests going big only after having created enough momentum to move the bigger pieces. 

A Relatable Example

To make this happen effectively, the author gives us a great exercise. Write down your goal 10 years from now and then jolt it down into different time milestones. If your destination 10 years from now is to get to “X,” where will you need to be 7 years from now? 

What about 5 years, 3 years, 1 year, 6 months, 1 month, a week, today? Think about that, and you’ll be closer to the achievement of your goals.

Big Idea #2: The One Thing

If you observe the most successful people of the world, you can easily notice how the majority of them achieved that massive success because they managed to focus on one thing and master it. 

Tiger Woods, Magnus Carlsen, Michael Jordan, Bill Gates, Cristiano Ronaldo, Conor Mc Gregor, and Steven Spielberg are just a few examples.

As the author says in his book, if you try to catch two rabbits, you won’t even catch one, just chase one rabbit and then try to get the other one. At least you’ll do this on a full stomach. 

To avoid such an unfocusing problem, the author has come with a powerful question that you should ask yourself every day to train your mind to refocus. 

The question is: “What is that one thing that you can do this week that, by doing it, everything else will be easier or unnecessary.” You do this and will have the most impact. 

A Relatable example

Science has proved how multitasking, as many people think about it, doesn’t actually exist. In fact, our conscious brain can’t do multiple things at the same time. This can only happen through the combination of your conscious and subconscious mind. 

Since, when multitasking, you consciously decide to multitask, your productivity will inevitably decrease as when you switch your attention from one thing to another, there is a time where your brain goes blank. 

This makes it engage in different areas of your brain that slow down productivity significantly. 

Big Idea #3: Manage Your Willpower

Your willpower is like a muscle, this means that the more you train it and the stronger it will become as well as the more you use it and the more it will be depleted of energies.

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This makes it crystal clear to us that if you use all your willpower doing petty things in the morning, for the rest of your day, you won’t have enough willpower to use for the activities that will make the difference in your life.

Can you recall those days where you worked hard, had to make many important decisions, or when you didn’t sleep enough and felt very tired? That’s a perfect scenario of depleted willpower. So how can you avoid such a depletion?

1: Spend your willpower on activities that matter first thing in the morning;

2: Make decisions fast, because the act of making them consumes a lot of glucose and willpower;

A Relatable Example 

To show how our willpower gets depleted just like a vampire does with somebody else’s blood, an experiment has been conducted years ago by some researchers. Two groups of people had to solve some mathematical problems in a room. 

Each person of the group was taken individually and brought into a room where to solve those problems, in that room, there was a jar full of marshmallows. 

To the first group, it was told that they could have eaten the marshmallows if they wanted to. The second group, instead, was forbidden to eat such marshmallows. The first group that was allowed to eat the marshmallows could resist more in solving the problems. 

The second group, instead, got burned out much sooner as they were using their willpower to resist the urge to eat the marshmallows.

Big Idea #4: The Success List & Thinking Big

Once you have found what is the one most important thing you must to do to become successful. You must also acknowledge how to prioritize the other activities in the best way possible. 

To become successful, you don’t need to be more disciplined, but you need to manage your activities better by building the right habits. The author advises prioritizing your work time ruthlessly above anything else. 

You shouldn’t be balanced whenever you are trying to succeed; be focussed instead, and don’t try to juggle too many balls.

Moreover, don’t be afraid of thinking big. You should think big but at the same time, as with the domino effect, focus on the little activities that will get the big goals to become true.

A Relatable Example

J.K. Rowling wasn’t afraid of thinking big when she wrote Harry Potter. Anyway, she had to focus on writing each day and getting this habit in order to complete her works. 

This proved to be a successful strategy as by adopting that long term view, coupled with the right consistent habit of writing, it was almost inevitable that she would have made it that big.

Big Idea #5: Use Those Productivity Tips

Finally, the author gives us a set of tips to use to maximize our productivity at work. One of those tips is using the 20/80 principle, stating that you should focus your energies on the 20% of things that will produce 80% of your results. 

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Moreover, the author goes even further with this rule and says that in order to find your most important activity, once you find your 80/20, you should repeat the process again and again until you get to that one thing.

Secondly, being aware of Parkinson’s law (stating that the more time you have and the more you waste), can drive us towards shortening our deadlines for any task we must bring to completion. 

Finally, the author talks about time blocking, a concept with which you should block all the time in your calendar that you should dedicate to your most important activities. 

This means that if somebody invites you to do something in a day you “time blocked,” you should say no to the proposal (using common sense, I would add) and reschedule it.

Relatable Example

Parkinson’s law can be easily understood by visually anybody that has gone to school. Do you remember when your teacher scheduled an exam for a specific date? Well, if you’re like the majority of people, you didn’t study hard until some days before the exam. 

Why? Are we all better learners in the last days? Not specifically, but due to Parkinson’s law, we do become more productive when we know we have less time to accomplish a task.

Conclusion & Takeaway

Success can only come by focussing on one thing and not many of them. Thanks to the advice given by the author, you now have the tools to cut through the clutter and focus on the things that really matter.

My Advice For You

Don’t take everything said in this book as the ultimate truth for success. Surely focussing on one thing will higher your chances that you’ll become a top-notch performer in that area. 

Anyway, success must be defined by you only, and if you believe that becoming successful is not strictly related to something professional, then you might also dilute your time to learn various skills. 

This won’t probably make you a top- performer, but it will still give you the chance to make it in a certain field by combining your various skillset.

About the Author

Gary Keller is the founder of the largest real estate agency in the US, the “Keller Williams Realty International.” Before getting so successful, he was scattering his energies on many things, causing him to suffer from psychological burnouts. 

Then he decided to focus on one thing only until he became so successful in life that he was inspired to write this book.

Reading Suggestions

  • “Deep Work” – Cal Newport
  • “Getting Things Done” – David Allen
  • “Essentialism” – Greg McKeown
  • “Atomic Habits” – James Clear
  • “Start with Why” – Simon Sinek 

How would you improve this book summary? Comment below and let us know so that we can serve you better!

Armin is an online entrepreneur and writer in the dating, psychology and spirituality areas of the self-help industry.
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