The document outlines the history of sound recording technology from 1877 to 2010, including key inventions like the phonograph in 1877, tape recorders in the 1920s, cassette tapes and compact discs in the 1960s and 1980s, mp3s and digital music in the late 1980s and 1990s, and ubiquitous recorded music today. Major milestones included Thomas Edison inventing the phonograph in 1877, cassette tapes and compact discs revolutionizing portable music, and mp3s allowing hundreds of songs to be stored digitally.