A sort of Ken Burns question

[David Powell]

I have a question for Paul, which I know is going to be answerable in general that there is a lot of overlap and differing opinions but here goes:
One of the ensembles I play in is billed as a jazz ensemble. Apparently jazz is a lot of different things to different ears. Recently we were asked to incorporate "Moon River", "Chatanooga Choo-Choo", "Sentimental Journey", and some tunes like those into our list for that client's party. We obliged of course because the gig paid well, but our varied repertoire includes mostly Real Book tunes that I consider jazz standards like Satin Doll, Gee Baby Ain't I Good, Footprints, Shine, Limehouse Blues, Caravan, All Blues, Angel Eyes, etc. I know in just what I've listed we cross some sub genres already. So the question is what really are the sub genres of jazz and what characterizes them and what is definitely not jazz, but just a pop tune from the "jazz era"?