This is one of my favourite books. It was one of the first books on magic I ever read (nearly 20 years ago) and remains, in my opinion, one of the best. It's on shamanism and I'm a witch, but I'm a pretty eclectic witch. In any case I think this book, while staying within a tradition, also transcends it.
It's not dogmatic, and it IS practical. If you try the exercises, they will work. In practical terms magic is about shifting energy, in any context. King shares a number of techniques, and discusses the sorts of situations in which you might want to use them. Not everyone will want to do everything, e.g. I am trained in various healing modalities and have no need to add huna healing to my repertoire. It's still interesting to read his description of it.
He also discusses the theory and beliefs behind these practices. His shamanism is a loving variety, and the seven principles on which it is founded are attractive and make a lot of sense to me.
I also find the book very readable and engaging.
I recently sent a copy to a 15-year-old grand-daughter who is developing an interest in magic. It's benign, easy to understand, and it works — what better introduction?