At the request of a member of a little band in which I sometimes play, I added Moonglow to my repertoire.
As ever, I used a Mini Filofax page. I wrote it out in the Key of G. I kept the chord structure simple, though I am aware that more subtle changes would have been possible.
What strikes me about this tune is the way it cleverly teases the listener and thus achieves its striking effects. For example, the first bar of melody sounds like an anacrusis but in fact it really is the first bar proper. Also, the first two bars are based on the chords of C major and C minor respectively, even though the tune is actually in G.
In its principal 8-bar melody, Moonglow uses a simple two-bar theme three times. You could hardly devise anything less complex. But look at the changing harmonies and you find the first B natural is harmonised against C minor, the next one against A major (making in effect A9th) and the third B natural is played against a D major (making in effect a D6th). The final two bars of the eight (all on the melody note of G - again seemingly very simple) are played over the beautifully shifting harmonies of G, G diminished, A minor 7th and G again. What a super effect that achieves.
And what about the Middle Eight? They start with a G7. Fair enough. Surely that will lead smoothly into C major?
Oh no it doesn't. We descend exquisitely through F#7th and F7th to E7th! And the next four bars go (as we might expect) from A7th to D7th - but there is yet another surprise: we slide through C major 7th on the way!
Mastering this tune with the band should not be difficult. There are only 16 bars essentially to learn, even though you have to play 32. I'm already thinking of the pleasure those teasingly beautiful harmonic games will give.