Can anyone recommend any good (not neccisarilly guitar oriented) theory books? I'm interested in the history behind awkward rules etc. that help explain some of the seemingly randomness of music. Anything with some practical guitar application would be nice but I'm tired of books helping you navigate through the preliminary stages with coloured diagrams illustrating the pentatonic scales, etc. Thanks in advance.
I also wouldnt mind knowing a history book about music, especially about the gregorian monks. I know what they said and to some (musical) extent why, but I dont know who, where, when or why.

If your just after plain theory, T/S, read the complete idiots guide to music and than mark levines jazz theory.
Good theory books....

I used the AB guids part one and two as well as the exercise books that go with it.

Currently reading and working my way through First year Harmony by William Lovelock (I have second year and thrid year but I havent got to them yet).

Currently reading Jazz Theory for Guitar by Mark Levine

Currenyly reading Jazzology by some dudes (its a red book, very good has lots of excercises to work through).

Other than that, I dont know lol.
Sat in a lab, curing diseases. They actually LET me play with chemicals!