The main body of the book is comprised of several essays, written by a select group of Jung's peers, which carefully explain his work. And Jung himself edited the essays, in order to assure that his messages were crystal clear. Jung provides an excellent introduction chapter as well.
If you are looking for an easy to digest book that covers Jung's amazing dream analysis techniques, Man and His Symbols is made for you.
Jung suggests that man's greatest adventure lies in the exploration of the inner world of the psyche. By getting in touch with the unconscious (especially through dreams), one is supposedly able to activate latent guiding powers that will help him become a stronger individual. Jaffé's essay details a case where a Jungian anaylsis is successful, and it convinced me.
For a basic grasp of the collective unconscious and the archetypal symbols and how they relate to you, this book serves. It's very easy to understand, and its simple language and many illustrations make it easy to work through.
The only disappointment is that the book is too simple. Given only a taste of the basic concepts, you are left wanting more depth and a wider discussion of Jung's ideas. As Ms. Von Franz says in the closing essay, "This book sketches only an infinitesimal part of his [Jung's] vast contribution to this new field of psychological discovery."