The book isn't so much about "why we sleep" but rather "why you should sleep more" – 350 pages of Walker telling you about study after study after study after study comparing well-slept to underslept people, and all of the afflictions the latter suffer from, often without even noticing it (and the consequences for industry and society).

While I found his contrived writing style annoying at times, the content is the kind of eye-opening that makes you want to buy a dozen copies just to give to your family and friends.