Solo or group vocal mainstream popular song performance in which the focus is on the singing. Typically songs are written by professional songwriters, and accompaniments (often with orchestra or big band) are prepared by professional arrangers. Distinguished from rock, jazz, country, folk, dance, and ethnic styles in which the performers generally handle both singing and accompaniment, and often write the songs as well. Developed in the 1930s and 1940s as singers increased in importance compared to the bands they sang with, and continued as a non-rock alternative from the 1950s to the present day.