The Jazz minor is sometimes known as the melodic minor ascending. The notion of a scale containing one set of notes on the ascent and another set on descent does not fit the useage of Jazz very well.

As the descending form is already a mode of the Major scale (6th or Aeolian), jazz musicians have adopted the more interesting ascending form.

The Jazz minor scale is very simple. It's a major scale with a flat 3rd. But the harmonic implications are profound...The Altered, Lydian b7 and Phrygian natural 2nd scales are all derived from this scale.

Sounds like I'm speaking greek? Actually, I am! But listen to the sketch and hear how smoothly the scale moves over the chords.

Do you hear what's going on over the Fm7b5/Bb7alt/Ebm part?

The scale Ab Jazz minor works perfectly over Fm7b5 chords. The B Jazz Minor works perfectly over Bb7 alt. So anything that works successfully over the first chord will work successfully up a minor 3rd over the second!

So the formula is: On minor II/V progressions, go up a minor third from the root of the II chord and start a Jazz Minor Scale. Go up a minor third from THAT to play over the V chord. Make sense?

For example:
Cm7b5 > F7alt > Bbm would be:
Eb Jazz min > Gb Jazz min > Bb Jazz min