I found this book helpful to make progress with my Vietnamese. This book is your typical classroom book. It's great if you have a partner to do the exercises (I had a tutor, since I couldn't take the class). I especially enjoy listening to the dialogues on the audio CDs and try to understand the language as it is spoken in real life.
The book is divided into about 20 chapters plus a couple review chapters (personally I don't think the review chapters are necessary and the same vocabulary is repeated on the summary pages, which makes the book much longer, thicker and heavier); each chapter contains relevant vocabulary, dialogues, and exercises. The downside of the book for me is that it's somewhat Americanized Vietnamese (for Vietnamese people living in the US) except for the Vietnamese proverbs at the end of each chapter (which are a bit hard to understand without someone explaining it to you); having spent half a year in Vietnam, there is some vocabulary that is completely useless in Vietnam (like fast-food, vacuum cleaner, etc.). Many dialogues are also setup more for a typical American life style, not the current Vietnamese life style. Also, there is one guy on the CD whose pronounciation is pretty sloppy and simply not very good. All in all, the CDs are a strong point, though, and the book has been quite useful.