Why We Sleep By Matthew Walker | Should You Read? | Book Review

When you search on Google or Amazon for the phrase “books about sleep,” Why We Sleep by Matthew Walker, PhD is the top search result. A New York Times bestseller, praised by the scientific community, and praised by the likes of Bill Gates, it’s no surprise this book is the top choice.

As is typical for me, I’m behind the times. Written in 2017, I was only recently made aware of this book’s existence. But better late than never.

I just finished reading the book and knew I had to share my thoughts. And I can’t be the only one who has never heard of this book before.

But instead of doing a typical book review, I will instead approach this from the standpoint of should you read the book. Since the book is already a few years old, reviewing the book doesn’t make complete sense. Instead, I will present what this book offers. From there, you can determine if you think this book is worth reading.

(Spoiler alert, it’s absolutely worth reading.)

So let’s begin exploring if you should read Why We Sleep. If you want to read it, pick up a copy here.


Matthew Walker, PhD is one of the world’s top sleep experts. Dr. Walker is the director of UC Berkeley’s Sleep and Neuroimaging Lab. He has authored, or co-authored, numerous studies on sleep.

Dr. Walker is a sleep scientist, and not a sleep doctor. This is a distinction he mentions several times throughout the book, and it’s important we understand this difference, too. Dr. Walker’s interest in sleep is from a research perspective. Therefore, he can make recommendations to the medical community regarding sleep, but he does not treat patients. Additionally, this means he has no affiliations (positive or negative) with any major pharmaceutical companies, as many doctors have when they prescribe only certain brand drugs.

Why We Sleep is the first sleep book by a leading sleep science expert. This may come as a surprise to you, but when you think about it, it makes sense. Most books about sleep take the form of a self-help book. Why We Sleep is markedly different in this regard.

The book focuses on understanding the science of sleep and how sleep impacts our health. However, very few recommendations are provided for improving your sleep. This means the book aims to educate you about your sleep, giving you the intrinsic motivation to make any necessary changes to your sleep health.

Simply put, this book provides education, not a prescription.


The book is divided into four parts: 1) This Thing Called Sleep, 2) Why Should You Sleep?, 3) How and Why We Dream, and 4) From Sleeping Pills to Society Transformed.

What’s great about this structure is that it’s sequential. Dr. Walker naturally progresses from defining sleep, to why sleep is necessary, to dreams, to how our sleep has changed.

And through this structure, Dr. Walker takes the reader from any prior knowledge about sleep to understanding the complexities of sleep.

If you have any educational training, you will recognize that this is a perfect model for how to teach a new concept to students. We, the readers, are Dr. Walker’s students, and he is an excellent educator.

Within this broad structure, each chapter only focuses on a few topics. This level of specificity allows us to learn the many sleep-related topics at a slow, but in-depth, pace.

For example, chapter two’s title is Caffeine, Jet Lag, and Melatonin: Losing and Gaining Control of Your Sleep Rhythm. Unsurprisingly, Dr. Walker is discussing maintaining a sleep rhythm (schedule) and how caffeine, jet lag, and melatonin can affect our sleep. It’s a simple, but effective way to structure these chapters for maximum understanding.

Writing Style

This book was written for the layperson, as in the general public. This is not a book for scientists or medical professionals (though they certainly can read it).

This means the language is simple and easy to understand. But don’t worry, Dr. Walker isn’t insulting our intelligence. He is exceptionally good at discussing complex topics in simple terms. Better yet, Dr. Walker frequently compares sleep topics to other topics we are likely already familiar with.

Dr. Walker proves once again that he is an excellent educator. His ability to relate sleep to other aspects of our life makes it not only easy to understand, but also assures that we never feel like we’re reading a textbook. And it’s this hybrid academic-conversational tone that makes his book feel like a quick read, even though we’re learning a ton of valuable information.

If you’re at all familiar with Malcolm Gladwell and his books (Outliers, etc.), this is the closest comparison I can make. Dr. Walker and Gladwell are both extremely capable of discussing complex topics in simple terms.

In fact, I’d argue that reading Dr. Walker’s book is fun. It feels like a knowledgeable friend is speaking with us, rather than a teacher lecturing us.


For as much praise as this book has received, it should be no surprise that it’s received criticism, too. I only mention this criticism to be thorough, rather than critique the book myself.

The main criticism is that Dr. Walker over-exaggerates and over-simplifies the facts. This is not to say he presents inaccurate information. Instead, some people argue that scientific facts are presented in certain ways to make sweeping generalizations.

For example, Dr. Walker frequently mentions that healthy adults should sleep 7-9 hours a night. This is an undisputed fact. Dr. Walker further states that sleeping less than 7 hours is detrimental to our health. This statement is true for many people, but not all people. And while many health problems are connected to poor sleep, science cannot say definitively that lack of sleep causes these health problems.

It’s these kinds of generalizations that upset a lot of people. Some have even gone so far as to accuse Dr. Walker of using scare tactics. I have to say I disagree with this criticism. He may use generalizations, but we have to remember that this book was written for the average person, not a scientist or medical professional.

Finally, in addition to his generalizations, some have argued he uses incorrect numerical data. For example, Dr. Walker mentions a 200% or 300% increase or decrease of certain data points. And critics argue that these numbers are mathematically impossible. But these percentages are absolutely possible, as a 200% increase is simply two times the original value.

Regardless of its criticism, these are just points to be aware of, and not necessarily a reason to avoid reading the book.


Why We Sleep is one of the most enjoyable reading experiences I’ve had recently. Because I am such a fun of Malcolm Gladwell, it was wonderful for me to read a book by an author with a similar writing style.

I believe this book is well worth reading for anyone looking for a solid foundation on the topic of sleep. After reading, you will have a basic, yet in-depth, understanding of the importance of sleep.

The most important thing for people to remember is that this is not a self-help book. Almost no specific recommendations are made for getting a better night’s sleep. Instead, the knowledge gained from this book will motivate you to get a better night’s sleep.

I would definitely consider reading this book. And as Dr. Walker mentions in his introduction, this is the only book where the author hopes you fall asleep while reading it.

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