First thing in order to get good profit of this book is to be aware of the date of its first publication (around 60's). Since then much have been discussed about both Stylistics and Linguistics but by that time the authors pointed out a few good important elements do discuss the uses of language with a scientific approach. If you don't have a background on the Stylistics studies, remember that this book brings a very specific view of what stylistics is and which aspects stylistics should focus on.
According to the authors Stylistics is the branch of linguistics that studies aspects of language variations. Considering that for each social situation one uses a different kind of language skills, Stylistics should study and analyse these variations according to social backgrounds and cultural contexts. Stylistics would focus on some of the same language aspects of nowadays Social Linguistics but looking for what Charles Bally called the expressive face of language.
The book is full of good analysis of uses of English and can be very interesting for the ones who desire to discover this language. Crystal and Davy don't offer any example of literary text as they believe that literature deserves a more carefull aprroach. Before the task of analysing this kind of text, Stylistics would have to grow on tradition as a Discipline so that people would be prepared to face the challenge of describing literary style. Regarding on this matter and considering the importance of training stylists, they offer a method to text analysis.