I can tell you where I was when I first read this book. I was flying to Washington DC to visit Michael Ungar and the Georgetown Staff. I read the book cover to cover over the course of that flight. At the time it was incredible how many insights this book had for me. Now it is a seminal resource that I reference my programming to ensure I am doing what is correct. 

For the record, these are not principles. These are more Rules of training. We can choose to not do the aspects of training Charles was referring to within this book. This may not lead to positive outcomes, but we do not have to follow these Rules exactly. 

If you read the book it is a how to guide on how to program. From Sets/Reps/TUT/Rest to Exercise Selection it is a seminal guide for a coach to remember when programming. Gems like an inverse relationship with sets and reps: more sets means less reps. Or Basic Reference Chart for TUT based on training quality: Relative Strength 1-20sec TUT, Functional Hypertrophy 20-40sec TUT, Hypertrophy 40-70sec TUT, and Muscular Endurance 70sec +. 

If you are not familiar with Charles, he was a huge influence on me personally. I followed that experience with attending multiple seminars and certifications he created and instructed. The pinnacle was attending a week-long internship with him in 2015. 

My programs over the years have been influenced by so many amazing coaches. Charles is right up there with the most influential coaches of my career. I consider myself partly responsible to continue on his legacy. I get asked quite a lot of how to learn more about Charles. A better question is where to start. Poliquin Principles is probably the best place to start.