After decades of groundbreaking instrumental and electro-acousmatic works, Horacio Vaggione’s latest composition, 24 Variations, is a computer music work for multi-track recording media that includes real time mixing and transformation of pre-composed sound files. It is often presented as laptop electronic concert music, and thus exists as an open-ended composition. Sound source materials are mostly acoustic sampled sounds of diverse kinds, processed by means of analysis-resynthesis procedures including granular, waveshaping, convolution, and other kinds of cross-synthesis and morphological processing. Live manipulation includes the mixing of precomposed sound files of varying sizes, as well as real time filtering, phase shifting, convolution and granulation. The word “variations” applies here to the transformations of the sound materials, as well as to the different contexts in which they appear. It also refers to the live performance aspect of the work, as each presentation can be considered as a different instance of the same class of materials. Source sampling and original sound processing of the sound file collection was done at the Centre de Recherche Informatique et Création Musicale (CICM) of the Université de Paris VIII where Vaggione is director and professor of Music. The present version was performed at the ICMC (International Computer Music Conference) in Göteborg (Sweden), on September 20th, 2002.