That is exactly what people in the music business discovered toward the end of the 1970s, when after three uninterrupted decades of expansion, recorded-music sales stopped growing. A new spurt of growth starting in the mid-1980s then carried through to the late 1990s, when the industry peaked with aggregate worldwide revenues of some $40 billion per year. Since then, problems have abounded.

Still, however, music is the most easily personalized and accessible form of entertainment and it readily pervades virtually every culture and every level of society. As such, it may be considered as the most fundamental of all the entertainment businesses.

Feeling groovy

Experimentation with reproduction of moving images can be traced back to the early 1800s. But there was apparently little interest in the mechanical reproduction of sound until the venerable Thomas Edison in 1877 developed yet another of his novelty items – a tinfoil-wrapped cylinder that was rotated with a handle. While he cranked the handle and recited the nursery rhyme “Mary Had a Little Lamb” into a recording horn, Edison's voice vibrated a diaphragm to which a metal stylus was attached. The stylus then cut grooves on the surface of the tinfoil and – voilà! When the procedure was reversed, the stylus caused the diaphragm to vibrate and the amplified recorded sounds to emanate.