Carl Philipp Emanuel Bach was among one of the earliest who contributed to the musical development in German & Austria region in the history of western music. He was active between 1740 and 1788. The six volumes of the Clavier-Sonaten und Freye Fantasien nebst einigen Rondos für Kenner und Liebhaber printed later in his life are greatly admired for its artistic level is comparable with the compositions of Haydn and Mozart. The thirty-seven compositions contained in the für Kenner und Liebhaber consist one common feature, the fantasy technique. This thesis will focus on the study of Emanuel's concept of fantasy and the application of fantasy technique in the für Kenner und Liebhaber. The writing consists of three chapters apart from the preface and the conclusion. The first chapter focuses on the related background reflected through Emanuel's life, this chapter describes the different musical environments of Berlin and Hamburg in the mid-eighteen century, and the contemporary musical thoughts of recognizing variety and differentiation of human expressions. The second chapter states the printing process of the für Kenner und Liebhaber. Emanuel's selection of music was based on the combination of three aspects: the popular taste, contemporary musical concepts and his own musicality. Later in the chapter the author will focus on three fundamental liberties of free fantasy: rhythm, tonality and material freedom. The third chapter discusses how the fantasy technique is applied in the für Kenner und Liebhaber. The author will analyze the six fantasies based on three features of the fantasy technique, the effects of the technique on the musical phrases and the influences on the structure of the sonata, and finally the processors of the technique transforming the rondo from simple to complex musical form. Many evidences show the style of fantasy suiting Emanuel's artistic talent the best. He freely applied features of other musical form in his fantasy, and yet used the fantasy technique in other types of musical in the most settle and refine manner. The für Kenner und Liebhaber is the best example of the fantasy technique and the essence of Emanuel's musical composition.