Vietnam is a fast changing place. Since the time that they first opened up the country to visitors from the US, cities like Saigon have undergone so much construction that a guide book from just a few years ago is sure to be outdated. This one covers things from the old to the new. It's the result of about six months of research from people who visited the area, and covers a lot of ground.
The primary emphasis of any guide book should be to familiarize readers with the country, its regions, what parts to visit and what to expect there. This book does a good job of that, giving lots of details about everything from historical landmarks to beach resorts, and full color photos.
The book also gives you background about the country, its history, politics, and how things developed into what they are now. Understanding the background and culture is important for the enjoyment of any trip.
This book covers the major regions, cities, towns, and just about all the places that a tourist would be likely to go. It won't cover every little town, and in some cases, resort areas are covered well but the surrounding towns are hardly mentioned. If a place warrants a few paragraphs, it would not hurt to mention when it also has a world class resort rather than making sure to list 25 hotels in the city next to it.
On the other hand, there are far more places mentioned than a person could reasonably expect to cover in a several trips, and most hotels mentioned also have their websites or email address listed, making it easy to visit those, and visit travel websites for more specifics.
There's a lot of information on different ethnic groups, how different areas compare to each other, and even a crash course on the Vietnamese language and even a few phrases in some regional languages. It's tougher to cover a language like Vietnamese, and this book tends to emphasize northern pronunciations (it doesn't tell you that.) It also uses some phrases that should be worded differently depending on whether you are talking to a man or woman, somebody older or younger, etc. but it doesn't tell you that part either.
Nevertheless, you should have no problem getting around Vietnam when using this book as a starting point. You'll want to use it to research your trip, and use it as a hands on guide once you get to Vietnam. I've been to Vietnam four times in the last 15 years or so, and would have found this book very helpful. It doesn't cover every place I've been, but points out a lot of places I missed.