Each of these books are very helpful because of the facts that they are practical, efficient, and direct.
They have proven to be practical because there is a lot of insight included on ways of approaching these different concepts and how to make it your own.
They have proven to be efficient because they are not extremely drawn out. This is a good starting point to explore other topics and at the same time, it is a great refinement of conceptualization for those who have already been exploring these topics.
It has proven to be direct because of how objective yet specific the information is. For someone who is wanting an unbiased perspective based on actual experience, these are good options. I love the workbook idea.
Also the art is beautiful. The material allows for easy notes and the print is bold enough to read without looking too closely.