"There are two groups of standards that help form the basic repertory used in jazz improvisation. The first group was created by jazz musicians directly from improvisation, experimentation and the analysis of musical forms, ideas and practices that were developed through study and the natural gifts of some of the greatest musicians of the twentieth century. This group codified jazz into chronological styles and provides concrete examples of its styles and concepts. The second group of standards is comprised of compositions written as popular songs during the first half of the twentieth century ... Every improviser is a composer who makes up melodies spontaneously. The model choruses give examples that can be studied, learned, broken into independent phrases and used to create other melodies that reflect more clearly what the improviser wants to say musically ..."--Preface