We’ve come a long way in capturing and reproducing sound, and in many ways, the journey has been a poetic and literal full circle. From Thomas Edison’s first experiments with waveform-engraved cylinders to the rotating dials of our iPods − and every touchstone devoted to preserving composition and performance since and after − we’ve amassed a timeline of 24 essential breakthroughs (be they physical tools or digital breakthroughs) in recorded-music and playback technology.