Steely Dan and the μ chord / by Malcolm Edmonstone

Those crazy jazz-rock dudes loved add2 chords so much they adopted the Greek letter mu as a moniker!

But they also taught us two other crucial things about that chord; 

1. That it sounds best in first inversion

2. That it must be used sparingly

Above you can see one of a thousand uses, this time judiciously placed in the chorus of Fagen's 'Morph the Cat'.