Book excerpt: A groundbreaking study of the trailblazing music of Chicago’s AACM, a leader in the world of jazz and experimental music. Founded on Chicago’s South Side in 1965 and still thriving today, the Association for the Advancement of Creative Musicians (AACM) is the most influential collective organization in jazz and experimental music. In Sound Experiments, Paul Steinbeck offers an in-depth historical and musical investigation of the collective, analyzing individual performances and formal innovations in captivating detail. He pays particular attention to compositions by Muhal Richard Abrams and Roscoe Mitchell, the Association’s leading figures, as well as Anthony Braxton, George Lewis (and his famous computer-music experiment, Voyager), Wadada Leo Smith, and Henry Threadgill, along with younger AACM members such as Mike Reed, Tomeka Reid, and Nicole Mitchell. Sound Experiments represents a sonic history, spanning six decades, that affords insight not only into the individuals who created this music but also into an astonishing collective aesthetic. This aesthetic was uniquely grounded in nurturing communal ties across generations, as well as a commitment to experimentalism. The AACM’s compositions broke down the barriers between jazz and experimental music and made essential contributions to African American expression more broadly. Steinbeck shows how the creators of these extraordinary pieces pioneered novel approaches to instrumentation, notation, conducting, musical form, and technology, creating new soundscapes in contemporary music.