What is sound design? What function does it have in the early 21st century and what role could it play in the near future? This book explores the current state of functional sound design, its recent history, its characteristic forms of labor and how it is deeply interwoven with everyday life practices. In four parts this book tries to give an answer to the question Why that Sound? with a historical overview on how the magic trick of sound design degraded from providing an incommensurable shock to obeying contemporary ideologies of efficiency; a large visual part with 80 figures documents and questions the current state of Sonic Labor between a sound designer's private workbench, manifold forms of design abuse, and continuous pitching detours; a cultural analysis of Living with Sounds explores how sonic signs are domesticated, how sonic patterns can be decolonized, and what cultural transmission they contribute to leads then to the final part of Sound Works: How is designing sound for the sonic consumers of today situated in a surveillance society between affective labor and silencing dispositives? In what ways can the protagonists of the contemporary sonic workforce transform the situation of sonic labor in the near future? For professional sound designers and sound artists, for design aficionados and passionate listeners, and for researchers in the fields of sound studies, design research and cultural studies this volume provides an essential introduction to sound design as well as a provocative critique of contemporary design practices and soundcultures.