Metal music is heavy, but what does that mean? Heaviness is not just a timbre or quality of sound-it's an experience of impact that listeners help create. This book combines methodologies from musicology, music theory, cognitive science, and performance studies to define heaviness as a cross-sensory experience and aesthetic practice. Heaviness is shaped by what we do when we listen, how we think about metal music, and how we relate to the people who make and listen to it. Despite metal's historical narrative of "leaving the blues behind," many aspects of the genre perpetuate legacies of blues' musical style and highly racialized reception-including headbanging, and metal's ideologies and aesthetics of oppositional authenticity, loudness, heaviness, and extremity. Musicians and listeners navigate their own way through this landscape of legacies, re-enacting the genre's ideologies and musical structures through their own headbanging and moshing. Metal musicians perpetuate the genre's norms and practices, which in turn provide a framework for the creation and distinction of new metal styles and experiences. Heaviness in Metal concludes that longstanding restrictions about who and what count as metal have begun to loosen, expanding the scope of what heaviness can mean, and to whom.