Rock music is a genre of music started in America. It has its roots in 1940s and 1950s rock and roll and rockabilly, which evolved from blues, country music and other influences. According to the All Music Guide, “In its purest form, Rock & Roll has three chords, a strong, insistent back beat, and a catchy melody. Early rock & roll drew from a variety of sources, primarily blues, R&B, and country, but also gospel, traditional pop, jazz, and folk. All of these influences combined in a simple, blues-based song structure that was fast, danceable, and catchy.