The few lines describe how to apply the Bebop Major scale on a II-7b5 - V7b9 progression. As known, these scales use some cromatism between specific diatonic (i.e. notes exclusively taken from a simple major/minor scale) tones, in order to get a simmetric scale (8 notes) that starting from a note spells clearly a chord both ascending or descending

For  this purpose we use the major bebop scale starting from:

II°b degree of the II-7b5 chord = V°# degree of the V7b9 chord of a given minor II-V

or from an opposite perspective

A BeBop Major scale which II-7b5 built on its VII° and the V7b9 chord built on its III° match a given minor II-V progression.

An example could help further:

Es. –> on a B-7b5   -  E7b9  we use the C major BeBop Scale.

The reasons of all this are more than one, and for the moment focus on the V7b9 dominant chord only.

As first, the use of the cromatism between the V and VI degree of the scale gives it a simmetry, allowing to reach a chord note on every beat (3 5 7 and b9).

In addiction to that, the underline concept of this scale is that it incorporates the tension-release of the V-I progression. And this is applyable on both compin’ and improvising situations:

- if you start from a Dominant 7 chord tone, playing such a scale both ascending or descending you spell a Dominant chord,

- if you start from scale chord tone (in our case C major), you spell the tonal center chord, that in the given example (B-7b5/E7b9) is A minor, relative minor scale of C major and both composed of the same chorf tones: A C E G.

Es.