In the twentieth century, music entered a new period of development and changein musical language. Modernism is an aesthetic position that underlies this period. This period saw a variety of responses that challenged and reinterpreted older categories of music, and innovations that led to new ways of organizing and approaching harmonic, melodic, sonic, and rhythmic aspects of music. “Innovation” is the term that best describes music in the twentieth century, because of all the compositions that pushed existing boundaries and genre definitions, like avant-garde music. Avant-garde musical ideas of a given period are different from traditional classical music in those periods in several ways: compositional processes, format of scores and performances. Many contemporary composers like John Cage, Henry Cowell, and George Crumb played significant roles in the development of twentieth century avant-garde music. In my final project document, I will demonstrate how George Crumb combined musical sound and visual elements with his poetic vision by using extended techniques and graphic notations to achieve his musical goal, in addition to how George Crumb’s musical aesthetics related to timbre are seen in his works, specifically in his Zeitgeist, Six Tableaux for Two Amplified Pianos, Book I. Moreover, a performance guide for this piece and Crumb’s extended piano techniques used will also be included in this project.