This 2-volume set, comprised of Heaviness in Metal Music Production, Volume I: How and Why it Works and Heaviness in Metal Music Production, Volume II: Learn from the Masters, offers a well-rounded insight into the production of heaviness in theory and practice. Using primarily ethnographic research which draws on interviews and engineering documentation from various producers across different generations, the distinguishing feature of the study is the song 'In Solitude', which was written, recorded, and produced by the researchers themselves. Written by practising musicians, producers, and experts in music technology and musicology, these volumes offer a comprehensive understanding of the interplay between structural, performative and technological components of a metal recording, the perceptual and discursive factors determining heaviness, and the relationship between creative freedom and technical demands in contemporary metal music production. Containing unabridged interviews with the producers about their conceptual understandings of heaviness and approaches to engineering ‘In Solitude’ - and enriched by nearly 300 illustrations of their sound engineering techniques - the material in the set is also complemented by contextual information about heaviness in metal music production, covering non-musical, associative factors that influence what is possibly the most valued feature of metal music – heaviness. Heaviness in Metal Music Production is a rigorous academic study that advances the field of metal music production research through an innovative and methodologically robust approach, and serves as a practical primer for professional musicians, recording engineers, and producers to improve their own production values, or to allow for experimentation with new approaches. It is also a vital resource for students of metal music, music technology and production, ethnomusicology, cultural studies, media, and communication, making it essential supplementary reading for advanced undergraduates, postgraduates, and academics engaged in these fields.