Beautiful Music as a radio format came out of the post WWII popularity of popular instrumental music, primarily orchestral. Which in turn derived from the creative and interesting orchestral arrangements of popular tunes by network and ET orchestras on radio in the 1920s and 30s. Lanza's book rather conflates Orchestral Popular Music on LPs, Beautiful Music on radio, and background music services which I think rather sells short each of those genres. They were all based on popular instrumental music and there are and always have been some overlaps but they were all handled and sold differently. "Mood Music" was a commercial tag used to sell records in the 50s just as "Elevator Music" was a pejorative reaction to the relative prominence of instrumental popular music on the radio and on the popularity charts and in commercial establishments and public spaces primarily in the last half of the 20th Century. Muzak was not the first wire background music service but was the most highly-capitalized in its formative years and the most cannily run until the 1960s. Many of the same musicians and arrangers who were responsible for Muzak and other background service music were recording popular singles and LPs as well as conducting and playing music on radio during the same period and earlier. Fascinating history to all those genres. The author of "Elevator Music" acknowledged me in the original edition but I was told left me out of the later one, perhaps because of my public differences with his viewpoint. But outside of Marlin Taylor's memoir Elevator Music the about the only popularly available stuff on those genres and is very entertainingly and even philosophically written. Perhaps one day after I am gone my own monograph will become available which corrects many of the historical errors in those books. Though it mostly consists of just the facts presented unvarnished. Nevertheless there is a drama in the histories of these genres.I never had a basis for comparison, just what I've read about the format and some of the methods that went into programming it. 'Elevator Music' by Joseph Lanza is a good book about the history of easy listening, mood music and the rise of Muzak. The KAHM webstream is pay-walled now, interestingly.