What defines a "musical work"? Traditionally, this question has been dominated by Western art music and its reliance on prescriptive scores. Yet, with the rise of recording technologies and the growing influence of genres like jazz, pop, and rock, the very foundations of music's ontology have shifted. In English for the first time, Ontology of the Musical Work: Scored Music, Jazz, Pop, and Rock explores these transformative changes, offering a groundbreaking framework for understanding how music is created, experienced, and valued in contemporary contexts. This book introduces a new theory of music production--one distinct from the conventional paradigms of writing and orality--that emphasizes the unique characteristics of recorded music. Using this perspective, it critiques the traditional focus on scored music and reimagines the concept of the "musical work," bridging the divide between Anglophone analytic aesthetics and Continental philosophical traditions. Ultimately, Ontology of the Musical Work redefines the cultural and aesthetic significance of jazz and popular music, offering fresh insights into their roles within a rapidly evolving musical landscape. A vital contribution to musicology and philosophy, this book equips readers with new tools to understand and appreciate the diverse ways music resonates in our world today.