In his brilliant, provocative 1966 essay, The Prospects of Recording, Glenn Gould proposed elevating – pardon the pun – elevator music from pernicious drone to enriching ear training. In his view, the ubiquitous presence of background sound could subversively train listeners to be sensitive to the building blocks, structural forms and hidden meanings of music, turning the art form into the universal language of the emotions that it was destined to be. In a not-unrelated development, Gould had somewhat recently traded the concert hall for the recording studio, an act echoed by The Beatles' release in 1967 of Sgt. Peppers' Lonely Hearts Club Band, an album conceived and produced in a multi-track recording studio and never meant to be played in concert. And while Gould's dream of a transformative elevator music never quite panned out, it is clear that from the 1940s through the '60s — from Les Paul and Mary Ford's pioneering use of overdubs in How High the Moon, to the birth of rock and roll with Chuck Berry's "Maybellene" in 1955, and on to Schaeffer, Stockhausen, Gould, The Beatles and many more — a totally new art form, enabled by magnetic tape recording and processing, was born.