This is the best book on birth I have read so far, and I have done plenty of reading. ;-) I hadn't heard of it -- it is not on a lot of the Listmania lists here, nor does it have many reviews. My husband selected it because it seemed authoritative, with an author who is an OB and the former head of the Maternal Health section of the World Health Organization. Unlike some of the slow-going tomes out there, this packs a lot of information into digestible chunks. It is definitely "biased" in favor of a midwife-attending, out-of-hospital birth and natural alternatives to drugs, technology, and surgery. Most persuasive were the statistics comparing practices and outcomes in various developed countries -- what we take for granted as necessary in the U.S. is not the norm, and European babies thrive just fine.
Even (especially!) if you are planning a hospital birth, as I am, it is worth reading because it goes through each medical procedure ("intervention") and its benefits and risks. This made clear how one intervention can "cascade" to more, but also made clear the circumstances in which I might want certain interventions. It highlighted certain danger areas where an overly cautious caregiver might hook you up with more interventions than you want, but it didn't have a full rebuttal to how to deal with that (perhaps there is none). I thought that demanding a second opinion was not very useful because wouldn't someone else with rights at the same institution just back up the original opinion?
It also has thorough lists of questions to ask a potential provider (OB or midwife or doula) or location (hospital or birth center). The one caveat I would add is that most hospitals in the U.S., at least not where I live, will give the "right" answers to all of Dr. Wagner's questions, such as no time limits on labor, freedom to eat, etc. So don't get your heart set on WHO's ideal model, or you will be :-(.
What was unpleasant, but useful, about the book is that it forces you to think about every contingency and plan to make the worst case scenario as much in line with your wishes as possible. Not something I would have dwelt on but for this book, and probably useful preparation.
This book teaches you that you deserve the best maternal/infant care and what that care should look like (probably not what you think!) and formulate your wishes for to cover every possible complication. It also emphasizes that birth is a dynamic process and doesn't always happen in accordance with our paper plans.