I bought Spontaneous Healing to be a companion to my other books by Dr Weil. I had truly enjoyed both 8 Weeks to Optimum Health and Natural Health, Natural Medicine. This is yet another excellent resource on how to integrate "alternative" medical practices with what you already know in order to achieve natural healing and wellness. Much of what he says are things that we already know: exercise is good, we need to eat more vegetables and fiber, get enough rest, and so on. But he also has new ideas presented here, as well as in his other books. I'm especially impressed with the breathing techniques. I was very skeptical that something as simple as breathing could have an impact on how I was feeling. But it really does make a difference! (The "waking up" technique saved me in college when I had no coffee).
My only criticism for this book is that the philosophy is "believe you'll be well, visualize being well, and it will happen." I agree that the mind plays a large role in our health, but I don't think that mind power alone will save you from all ailments. One example in the book is actually a woman who beat cancer without going through traditional treatments or chemotherapy. I find that wonderful and inspiring, but a bit unrealistic.
This book focuses on Healing in particular, so I would definitely take that into account when making a purchase. It talks about overcoming various health problems and has several good tips about health in general. But unless you're specifically looking for such a resource, I would recommed getting a book that covers health in a more general way such as Natural Health, Natural Medicine. If you're a pretty healthy person, this book really isn't really necessary.