I should have known better than to read a book with ", PhD" behind the author's name.

1.5 stars. There are a few interesting bits of information in here but I doubt you'll come across anything you don't already know until chapter thirteen.

This book has many other troubles. Walker's understanding of basic neuroscience is simply incorrect. No, the brain and the mind are not ontological equivalents according to modern neuroscience. His writing is exhausting. He is loud and passionate, arrogant and condescending, repetitive and boring. Imagine watching twenty poorly researched TED talks, delivered with viscous gravitas, one after another. Matthew Walker, PhD, feels the need to constantly remind the reader that he is a scientist — with his own sleep laboratory! — and that he is doing science at his laboratory in the University of California, Berkeley and that he is a scientist and that science says that sleep is the centre of the human experience and that he is a scientist. However, despite his employment as a scientist, he lacks proper references, endnotes, or even correct footnotes. His grammar and sentence construction are atrocious.

This book could have been an A4 PDF infographic. Despite reading the paperback I felt like I was on Twitter or Reddit from beginning to end, steeped in pop science hyperbole, so perhaps an infographic it should have been.