Yes Ian, I wish I understood it better. I guess it's exciting records like Exus Trek that got me into Northern though, because they were unusual. Ditto when I first heard Towanda Barnes thought it sounded a bit like Motorhead! There's a whole bunch of Northern records that I really don't get and I think it's the ones that follow a pop formula, intro-verse-chorus-verse etc, and played in an obvious key which would be chosen for pop as most palatable, ensuring a hit. But of course it's impossible to sumarise and you should never say "all northern".
As for writing a book about it, you, Rachel and Michele should definitely get together, I know a good graphic designer....
Lisa x