9781422277386

7 D ecades ago, music lovers had only two options for hearing music without going to see performers play live. They could listen to the radio, not knowing what song would be played when. Or they could buy recordings, first on vinyl records, and then on cassette tapes. By the 1960s, smaller, battery-powered radios meant people could take music with them wherever they went, but they still did not have the choice to hear a favorite song when they wanted. Some cas- sette players and, later, CD players were also portable, but in many cases listeners could not share the music with other people since they listened through headphones. Today, people around the world streammusic through a variety of devices con- nected to the internet. Companies have created services that let users choose from huge libraries of songs and hear the tunes they want when they want. Having this choice is called on-demand streaming. In some cases, consumers also have the option of downloading songs they purchase onto their own computer or other devices. Or they can simply pay a monthly fee to access a musical service’s offerings. They also can listen to streaming radio stations. Users might not know the exact song they will hear at any moment, but their musical tastes shape what kind of songs they’re likely to hear. While CDs, records, and cassettes still exist, more people now access their music through streaming services. The technology that makes streaming music possible has been around for less than 30 years. At the heart of it is the internet, which since the 1970s has helped peo- ple use their computers to share information around the world. But it took many de- velopments to go from sending emails or small amounts of data through the network to be able to stream music with high-quality sound. The development of the World