There are so many good things about this book, but I will focus on two that earned this a four-star rating.
1. Science, science, science. So many running/fitness books out there are based on the past. Running books especially are rife with this. "This is how the great of 30 years ago trained and it worked, so no need to change." Hutchinson fills this book with citations and explanations of the science behind endurance.
2. The section on the psychology is astounding. I have been able to use these principles in my own running and for athletes that I coach. The section on the pain cave is absolute gold.

If you're not all about reading data, you can skim those parts, but the principles that he sets forth are solid foundations for pushing limits as an athlete.
informative reflective slow-paced

The full title of this book is actually very apt since it describes exactly what this book focuses on. There was a quite decent split between discussions and theories around how the mind affects performance versus the actual limits of the human body. Most of these discussions went quite deep into the scientific literature regarding each subject which made the book feel very well researched. However, if you're looking for practical advice and ideas on improving your own endurance performance, there isn't actually that much here for you. This is definitely geared more towards either top level athletes or people curious about the peak performance of the human body in general.

I enjoyed the writing though with the book doing a good job of keeping me engaged by interspersing the deep, scientific stat-dumps with anecdotes and human-relatable case studies that gave us an interesting context. There were maybe four or five cases where the author got lost in the numbers and seemed to drone on a bit too long, but even in those cases, you could argue many people would find that extra detail fascinating. The backdrop of the entire book is the 2-hour marathon attempt which we come back to every few chapters and which worked well for having an example of the ideas the author was discussing.

I don't really have anything negative to say about this book. It delivered exactly what it promised and was both interesting and informative. It covered a wide range of disciplines, ranging from ones I knew quite well like running and cycling, to more esoteric ones like free diving and speed walking. There's probably something here for anyone with an interest in the limits of human performance and endurance. It's very honest in the current limits of our scientific knowledge though, so don't expect too many definitive conclusions or practical advice.

Fascinating. An awesome look at the mental and physical limits of the human body with tons of examples and studies. Hutchinson finds a great balance between discussing what we can scientifically measure and what we just can't discern with current technology. Informative and I imagine quite affirming for those that truly believe in mind over matter.

Recommended for athletes and anyone that finds psychology or studies of the brain interesting.

Who knew that in 11 days of reading this book something special would happen. Turns out I might have a supervisor to peruse these exact academic questions.

Don't get me wrong, I am a total sports science junkie & have probably read just about everything Alex Hutchinson has ever written on the internet. But...I did not find this book as fascinating as his articles. Maybe it's just that I enjoy this sort of thing more in the short form than in the long form, or that it's about human physical endurance, writ large, rather than specific to running science in particular. Or that I felt like I'd already read a lot of this before in previous articles he's published. I dunno. I'm glad I read it and enjoyed parts of it, but a lot of the time I found myself zoning out and just trying to get through a less enthralling section.

Interesting look at the limits of human performance at the edge of our limits. Ultimately it offered a lot of insight into things that aren’t the popular belief (for example we don’t need to be guzzling gallons of water on a long bike ride), and showed that cognitive expectations in performance, like in most fields, are ultimately the final barrier to the next milestone.
informative inspiring medium-paced

Pretty much highlighted the whole book. If you're an endurance athlete, read it.

Lot of modern science. In particular how we're starting to learn a lot more about the interplay between psychological and biological factors, and how they're far less separate than has historically been assumed.

I'm always a huge fan of anything Alex Hutchinson writes. This book did not disappoint. Although it does leave you thinking "No one really knows how any of this actually works."