The concept of headphones evolved from the telephone earpiece. Headphones were first used over 100 years ago by AT&T line repairmen and telephone operators for the same reason that they're used today -- to keep unwanted noise out and wanted noise in. Early radio fans were probably the first to listen to music through headphones, and when stereo reproduction was invented the headphones' place in rock and roll was assured.

  Before this invention, switchmen were prone to suffer headaches from telephones pressed against their heads with elastic bands.