Artificial intelligence (AI) is impacting a growing number of domains in ways both beneficial and detrimental. It is even showing surprising impacts in the Arts, provoking questions fundamental to philosophy, law, and engineering, not to mention practices in the Arts themselves. MUSAiC is an interdisciplinary research venture confronting questions and challenges at the frontier of the AI disruption of music. It aims to analyze, criticize and fundamentally broaden the AI transformation of three interrelated music practices: 1) listening, 2) composition and performance, and 3) analysis and criticism. For each practice, and grounded in two specific music traditions (Irish and Swedish), MUSAiC will document and critically analyze the impacts of and ethical issues surrounding AI. MUSAiC will formulate and implement the first music pedagogy for AI, the lack of which continues to result in the creation of AI systems that have only a surface knowledge of music. From this pedagogy, MUSAiC will develop new holistic methods for understanding and benchmarking AI, and improving them and their application. It will implement and test novel AI systems that dynamically adapt to specific users as “digital apprentices”, aiming to bring human-AI music partnerships to new levels of fruitfulness. The outcomes of MUSAiC will facilitate applications of AI to music in robust and responsible ways, impacting a wide variety of stakeholders. It will not only prepare music practitioners and audiences of the present (human and artificial) for new ways of listening, working, appraising, and developing the art form, but will also pave the way for analyzing, criticizing and broadening the AI transformation of the other Arts. Three overarching objectives include both humanistic and technological dimensions. The first objective is to survey the cultural impact and criticism of AI, especially applied within creative practices. The second objective is to develop music pedagogy for machines, which includes the evaluation of the resulting systems. The third objective is to develop and explore novel co-creative partnerships with AI. Within each of these are specific threads of work contributing to the domain of AI and music (and Art in general), as well as engaging different communities, from developers to practitioners to the public. The questions and challenges addressed by MUSAiC are uniquely situated at intersections of music and computer science. The project moves beyond studying existing AI technologies in music practice, to involving artists and their practices for music culture production in the development, use and analysis of new AI technologies from the bottom up. MUSAiC is humanistic in the sense that it focuses on how AI technology impacts culture and culture production, e.g. How can AI partnerships facilitate and hinder music creation? MUSAiC is scientific in the sense that it answers fundamental questions about the nature of AI technology, e.g. What does an AI perceive when listening to music? MUSAiC is technological in the sense that it addresses questions of improving AI technology and its application, e.g. How can we build an AI that listens to music, and improve its understanding of music in unique domains with limited data?