Back in the workplace, I hooked and wondered if "really", it could work. So I NVC with my own colleagues test guide and there, I found myself amused to see it could work well.
So of course, one does not become champion of NVC overnight just by reading a book. It would be too easy. Rosenberg's book is just a map and it is you who are the pilot and as with any art, it takes practice and lots of practice.
What is recommended is to start making NVC experiencing ... nonviolence, history of his own reflexes and feel their muscles in this area. Then it will be easier to move on to more operational phases. It is not good overnight and opportunities for missteps are numerous.
The NVC process can disconcert because it goes against what we are used to in our modern societies, but it works well. Listening to his feelings and those of others has great utility for large and small conflicts. It is a powerful tool available to everyone.
This book is a good basis for entering the field of non-violent communication.