That Jazz Dance book got an amusing pasting in the Wire this month. I'm not a big fan of that sort of music, but I too like genre books & can imagine its a pretty interesting read in its own way.
Most of the ones I would mention are in here, I think. Altered State, Energy Flash, Last Night A DJ..., Rough Guides Reggae & Rock, Love Saves the Day and Wake the Town... all get my vote. Nick Tosches is a great writer too - his country one is very good. Also, I was really impressed with how good John Robb's Punk oral history was (maybe the best I've read on the genre?) & am looking forward to his post-punk one, with a cd also coming out featuring tracks from a whole raft of Blackpool bands as well as many others. Oh, and Songs In the Key of Z is great (if you can call outsider music a genre).