A question for a more erudite music transcriber than I. I downloaded a transcription of Poor Butterfly from www.marcopanascia.com It's interesting to see Oscar Pettiford's take on the tune written out. Check it out; his lines are gorgeous, and I now can see what I've always loved about hearing his playing. But my question is why has Panascia written it out without a key signature? It seems to me that he could have spared himself a lot of accidentals by simply writing it in Ab. Am I missing something here? Thanks.