I wish I could say more nice things about this book but the narration has changed drastically towards the end and I ended up gliding through pages instead of reading. Walker is a sleep scientist determined to find out why we sleep and what happens if we don't sleep enough. During the first half of the book, he successfully builds a compelling argument towards why sleep is important for us and I was completely blown away with the science. Sleep is the natural remedy to most of the biological problems that we currently face. It improves memory, relieves us from painful memories, improves our creativity, makes us emotionally stable, protects us from infection by boosting the immune system, repairs our cells, decreases the chance of getting a heart attack or cancer. There is no other medicine in the world that can do all of these things without side effects . Indeed, natural evolution is a miracle.
I had two major issues with the book. One is using anecdotal evidence to draw conclusions that are not backed by the scientific scrutiny. For example, Walker uses evolution to explain how children could have evolved a shifted circadian rhythm, this argument is very silly and not backed with any research. The second issue is the alarming narrative that Walker chose in the second half where the book becomes completely preachy, borderline scary. Of course, sleep is important but I don't want that to be written in every sentence. It is repetitive and boring.
I was disappointed because Walker is an extremely good scientist. If he steered away from these anecdotal evidences and struck to his science, this book would have been much better. Overall, a decent read. You could also read a small article that summarizes all the findings and be done with it. This book took a lot of time to give the same message.