Good guitarists have a vast repetoire of harmonic material to draw from. Even in the pop, rock, and blues genres, where pentatonic and blues scales make up the bulk of scales used in improvising, there are times when those scales don't provide the correct color for particular situations. Nor does a 'typical' minor scale, like the natural minor (also known as aeolian). These are times when a guitarist might look to a more exotic sounding scale, like the harmonic minor...

Lesson: The Harmonic Minor Scale
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