Well this isn't a book at all. It was a computer based training course lasting about 8 hours, including video and audio. There is a module for each of the cognitive functions. That isn't in of itself unique. What is unique is that the creator of the course (Vicky Jo Varner) trains you on what to look for to recognize when people are using each of those function attitudes. What exactly does Ne look like? What does Si look like? She will tell you. In addition to quoting Jung, she extensively quotes some of the more well known experts in the area - Berens, Beebee, Nardi, etc. She describes each of the 8 functions it in a fair amount of clarity, using words and visuals. Then on top of that, she provides links to numerous videos that demonstrates each of the 8 functions in action and there are also homework assignments which allow you to practice what you have learned. I loved this course. I learned more about functions in this course than any other place. It wasn't cheap, but I thought it was well worth it.