When I began teaching photography I found that I had little to impart other than the way I worked, and I was aware of the danger of merely encouraging groups of imitators.  [ ! ]  Only the strongest minds and imaginations can overcome this form of “parrot” education.  It became obvious to me that there must be some bridge between the basic theory of the medium and a potentially creative means of application.  I felt it essential to translate the arcane principles of sensitometry into a system of applied craft which would be both precise and adaptable by the individual to any practical or expressive aspect of photography.  Out of this need was born the Zone System, which I formulated at the Art Center School in Los Angeles with the cooperation of an important instructor, Fred Archer.
— Ansel Adams, The Negative (1981, x-xi)