This book can be summarized in three words: get enough sleep. Beyond that, there isn’t much in the book that will surprise you. The author does a thorough (too thorough, in my opinion) job of describing all the ways sleep helps your body and how many ways lack of sleep hurts you. It really comes down to the same thing: get enough sleep. That’s what your mother told you. He describes many experiments, some of them ingenious, sleep researchers have done to prove the benefits of sleep. Sleepy drivers are more likely to die in a car crash. Duh. And so on. The workmanlike prose is very readable and understandable to the lay reader. I doubt reading this will change anyone’s behavior, especially since those who believe they function well on four hours a night aren’t likely to read it and will scoff at it if they do.