I have been playing and learning music by ear for years on numerious instuments. I find instructions books, tapes and CDs, usful for are the filler notes and techniques.

The most obvious for the Cajun accordion would be the use of octives. I probably would have spend months or years trying to figure them out if Dirk had not shown them on his video.

My personal preferance for banjo and dulcimer music are tabs, for the fiddle, sheet music. But for any instrument, my first chioce would be video CDs or tapes.

That is what works for me, you mileage may vary.