Jazz originated and evolved in a free market economy and complex mutual relations with unregulated social conjuncture. Coping with social challenges during the Progressive era (1890-1920) contributed to the partial emancipation of marginalized groups; however jazz, in its first decades, remained directed to the general need for mass entertainment (the "jazz era" in the 1920s). The artistic development of jazz was therefore temporarily delayed during the economic crisis, Great Depression and the new recession of the late 1930s (1929-1938). The first movement in jazz that could be considered to be an art for art's sake, while renouncing any populist elements, appeared in 1939 Coleman Hawkins' Body and Soul recording. Market and social conditi...