This document provides an overview of several genres of 20th century music, including jazz, country music, rock 'n' roll, and traditional pop music. For jazz, it outlines the history and origins in New Orleans, as well as styles such as swing, bebop, and Latin jazz. Country music originated in the southeastern US and features folk styles and ballads. Rock 'n' roll evolved from blues and incorporated infectious rhythms and syncopation. Traditional pop popularized vocalists accompanied by orchestras in the 1950s.