Abstract
Complications encountered in the α ↔ β phase transition in quartz have long puzzled workers. Experts now believe that this involves a third intermediate (incommensurate) phase. A theory of this has been proposed and favorable comments about it have been made by experimentalists. While I think that the basic idea is interesting, I am not happy with the way it has been developed. This paper is my attempt to do a critical review of the slightly different forms of the theory that have been proposed.