Lindoz. From what I am learning at school at the moment I understand that Jazz Harmony is built on the Harmonic Minor Scale and its chord extensions - 9-11-13ths and this results in all the "unusual" chords that you mention. There are lots of jazz theory sites that deal with this on-line. The Blues scale has only 6 notes and for best effect is played over Major Scale Chords which results in the "Blues" sound. I am at the beginning of my studies in this but someone with more knowledge may be able to add to this. Jazz Harmony modulates very quickly in and out of Harmonic Minor and Major keys pivotting on common chords so there are endless opportunities for harmony.Popular music on the other hand uses Major and the Natural Minor scale.This is the basis of what I am learning at the moment -the chords can get very involved to play as you have to keep the root in the base or split the chord up amongst the band but you can use any notes of the chord for vocal harmony which makes it easier. Thats just my two bobs worth if iit helps.Cheers Jean.

[This message has been edited by Jean Olivia (edited 05-31-2002).]