The cassette tape is the audio equivalent of the AK-47: cheap and easy to mass manufacture; highly usable with the minimum of skills and experience; and a symbol and tool of revolutions. Marc Masters doesn’t use that metaphor in his excellent and truly exciting book on cassette tapes, but he doesn’t have to. He outlines the story of how the cassette came to be the dominant recording medium on a global scale during the 1980s and into the mid-1990s, and by doing so shows how essential cassettes were to so many musical movements that they would have been impossible without the tapes that, as he points out, are so easy and satisfying to hold in your hand.