The bebop dominant scale or the seventh diminished scale is derived from the Mixolydian mode and has a chromatic passing tone between the flatted 7th (♭7) and the root. Barry Harris explains that it is derived from a dominant seventh chord from the root, and a minor 6th chord (m6) from the second degree. It has all the notes in both the major scale and the Mixolydian scale of the same root. This scale is often used over dominant seventh chords and all extended dominant chords, and over II-V chord progressions. According to Michael Miller, "[w]hen someone says they're playing 'the bebop scale,' this is the one they're talking about."
