"For the people who make them, music recommender systems hold a utopian promise: they can broaden listeners' horizons and help obscure musicians find audiences, taking advantage of the enormous catalogs offered by companies like Spotify, Apple Music, and their kin. But for critics, recommender systems have come to epitomize the potential harms of algorithms: they seem to reduce expressive culture to numbers, they normalize ever-broadening data collection, and they profile their users for commercial ends, tearing the social fabric into isolated patches of atomized individuals. Drawing on years of ethnographic fieldwork, anthropologist Nick Seaver offers an account of how the makers of music recommendation navigate these tensions: how product managers understand their relationship with the users they want to help and to capture, how engineers imagine the abstract geography of the "world of music" as a space they control and care for, how scientists conceive of listening itself as a kind of data processing. The book rehumanizes the algorithmic systems that shape our world, foregrounding the ideas animating the people who build and maintain them. Seaver braids together the thinking of programmers and anthropologists, opening up the cultural world of computation in a vividly theorized book that ranges widely from cosmology to calculation, metaphor to myth, and captivation to care"--