The concepts are presented in an informal, personal way almost without displaying any formula. At the same time, the author makes a point to find an exact number for his very own life. During his research, the authors identifies and explains ethical and methodological problems. For instance, some aspects of the human life such as its dignity can not be measured in money.
Personally, I liked most the approach of the priest in chapter 39, who says (my translation):
You discover your value when you enter into relationships with other people.
At the end of the book, the author averages the values determined by the different concepts. This is not the best estimate in my opinion. A better way would be to sum up the different values.
All in all, a thought-provoking, easy-to-read book which I really enjoyed.