The CJO is Chicago’s oldest professional jazz orchestra in continuous operation and one of the oldest jazz repertory orchestras in the country. When Jeff Lindberg and the late Steve Jensen first came up with their big band concept in 1978 (founded as the Jazz Members Big Band), they could not have predicted the remarkable metamorphosis that turned a group of first-call musicians into what is now known as the Chicago Jazz Orchestra, a 17-piece premiere jazz ensemble that has garnered both national and international recognition.