Oxford Music Online has a great article that goes into a lot of detail - <a href="https://doi.org/10.1093/gmo/9781561592630.article.44010" rel="nofollow">https://doi.org/10.1093/gmo/9781561592630.article.44010</a> and fittingly remarks that<p>>The organ is, together with the clock, the most complex of all mechanical instruments developed before the Industrial Revolution. Among musical instruments its history is the most involved and wide-ranging, and its extant repertory the oldest and largest. Despite its essentially indirect and therefore relatively inflexible production of sound, no other instrument has inspired such avowed respect as the organ, ‘that great triumph of human skill … the most perfect musical instrument’ (Grove), ‘in my eyes and ears … the king of instruments’ (Mozart, letter to his father, 17–18 October 1777).<p>Stephen Malinowski's famous YouTube channel of animated graphical scores has a great selection of organ pieces: <a href="https://www.youtube.com/watch?v=JXaCmhAMnHs&list=PLA20FE13E9AC56564" rel="nofollow">https://www.youtube.com/watch?v=JXaCmhAMnHs&list=PLA20FE13E9...</a><p>St. Cecilia, pray for us!