‘Hot clubs’ proliferated all over Europe and the United States during the 1930s. For a brief period (1935–6), they joined forces in an International Federation of Hot Clubs (IFHC), the main purpose of which was to link together devotees in search of American hot jazz recordings at a time when they were difficult to find and buy in Europe, since that sub-genre was less popular and commercially successful than what was then called ‘straight’ jazz. The expression ‘hot jazz’ was coined by jazz musicians at the end of the 1920s and referred to a style based on performance and improvisation rather than on the composition and performance of written parts. A founder of the Hot Club de France (HCF) in 1932, the French jazz critic Hugues Panassié was the first to establish a hierarchy between these two styles: