This book is metaphorically right on in regards to releasing the thing(s) that keep you wound up, things that hinder your worship and relationships.
Henri Nouwen published many books that were very short, yet were/are quite helpful to the growing spiritual life of many. This book, a short book on the life of prayer, is quite useful at helping us open ourselves to the Holy One.
The book is really an exposition of one image-the life of prayer is a life lived with open hands. Nouwen then leads us to understand open hands are a necessity because open hands/lives mean we are not captured by fear, fear being the opposite of love, but open to God. As we open our hands to God we begin to accept the good gifts of life and live lives of hope. We are able to care for others because we are no longer focused on ourselves. This life changing power is revolutionary he says because it forces us to question the world around us and address that world.
While it would be overly reductionist to say the sum total of the book is stated above, gaining more requires lengthy reading, meditation and surrender to the image of open hands. If you want a how to book, this is not it. If you want something to help you surrender to prayer and experience prayer in its depths, this book is quite useful and I would recommend it