Rock and roll is a kind of popular music, developed primarily out of country, blues and R&B. Easily the single most popular style of music worldwide, rock's exact origins and early development have been hotly debated. Music historian Robert Palmer has noted that the style's influences are quite diverse, and include the Afro-Caribbean "Bo Diddley beat", elements of "big band swing" and Latin music like the Cuban son and "Mexican rhythms". Another author, George Lipsitz claims that rock arose in America's urban areas, where there formed a "polyglot, working-class culture (where the) social meanings previously conveyed in isolation by blues, country, polka, zydeco and Latin musics found new expression as they blended in an urban environment".