This document discusses the history and development of popular music and its evolution into pop music. It notes that popular music refers to music popular within a specific region, while pop music originated in America as a commercial genre influenced by market forces. Some key developments discussed include ragtime and minstrel songs being early forms of mass-produced popular music; rock and roll emerging from R&B music and incorporating electric guitars; and Elvis Presley becoming a pop phenomenon through his television appearances in the 1950s.