Yes, I have that book, but I did not read it completely yet. It is indeed very interesting, not an easy read, but as you wrote, it certainly gives a lot of insights. BTW, I also like older music very much as well, 19th century, the great French organ repertoire, baroque music, from my organist background. And still older music from the renaissance and the middle ages, my wife does a lot of middle ages music on replicas of medieval instruments (see the other thread where I posted a picture of a organetto) and gregorian chant.