Harris wanted musicians to practice manipulating intervals. For example, if you are playing a melody and the next note you hear in your head is a Perfect 5th away, you should be able to jump that 5th flawlessly, regardless of what key you are in or what scale the chord chart says you are supposed to be playing.
Intervallistic Concept By Eddie Harris - Jamey Aebersold Jazz eddie harris intervallistic concept pdf
Eddie Harris – The Intervallistic Concept (Overview) Harris wanted musicians to practice manipulating intervals