Book excerpt: Hyperimprovisation is the first book to focus on the unique potential of computer-interactive sound improvisation. Instrumental improvisation, through the intermediacy of computers, allows musicians to create and modify large scale and long term structures at a highly polyphonic level, yet still in real-time. Computers also allow the construction of hyperinstruments, with many levels of explicit control of sound generation and transformation. Further, networked improvisation allows mutual—or competitive!— adaptation of the performing interfaces and mechanisms by several performers, again, in real-time. The achievements and future possibilities of the “hyperimprovisation” which is released by computer technology are explored in this book.