What is impressive is that it feels really passionate about teaching and he does not hesitate to "give" his knowledge.
According to what is written, it planned to make one or more other books with other chord progressions, like blues or minor turnarounds, it's pretty frustrating to see that he has not been able to personal writing because it would have been very helpful to me.
As usual it is not necessary to retain all by heart and some examples may seem redundant, but by dint of working in the ear and fingers acquire automation.
Obviously highly advised, whatever your level.