What is experimental music today? Recent attempts to define or identify examples of experimental music have been cautious and subjective, offering very little guidance to anyone with an interest in this field of activity. Is experimental music a historical event that refers only to John Cage and his influence, or does it have a greater spread and longevity? The development of this musical practice over the last 45 years merits a fresh definition and discussion. An experimental approach is not identifiable in specific sounds or techniques, and its scope would be drastically limited if it were judged on the basis of social or aesthetic groupings or self-identifications of composers.Experimentation is a way of working. It pushes past that which is known to discover what lies beyond it, finding new knowledge, forms, and relationships, or accepting a state of uncertainty. For each of these composers and sound artists, craft is developed and transformed in response to the questions they bring to their work. Knowledge of scientific, perceptual, social, or linguistic phenomena become catalysts in the pursuit of new sonic possibilities. Musical materials may be subject, among other treatments, to systemization, observation, examination, magnification, fragmentation, translation, or destabilization. These restless and exploratory modes of engagement have proliferated over recent decades, expanding the scope of musical practice.