RUBATO is a universal music software environment developed since 1992 at the Department of Informatics, University of Zurich, under the direction of Guerino Mazzola. RUBATO is based on the concepts, models, and results of modern mathematical music theory and therefore realizes a powerful long-term strategy of research and development in the field of music informatics. RUBATO is designed for the collaborative interaction of components for specific tasks such as analysis, composition, performance, and logical or geometric operations. Such a component is called RUBETTE® and may in principle serve for any task provided that its interface with other RUBETTEs is based on the exchange of the universal data format of denotators. Supported by an international scientific collaboration, RUBATO and its RUBETTEs have been realized in a number of platform-dependent implementations and is now avaliable as an open source and platform-independent Java software with codename RUBATO composer. The international community of music software developers is cordially invited to contribute in a global collaborative enterprise any RUBETTE of interest to RUBATO’s repository of components.