I really like Adam's Photography and I have used the Zone System. Nevertheless, I found Adam's description of the ZS in The Negative the most frustrating, obtuse and confusing description out there. Why flounder around trying to understand something presented in such an opaque manner. Go get "The Practical Zone System" by Johnston. Read it and follow the lessons. The zone system will then make sense. Then go back and read Adams--all will finally fall into place.