ED, that's the sine qua non for ballad tunes and their history prior to 1700 (and some later), for the most part making Chappell's PMOT obsolete (except for non-ballad and later tunes). All 540 tunes (earliest known copies) in it are given as ABC's on my website. It's been out of print for some time, but you can sometime find used copies for $50-60 on the used booksellers websites. It was cheaply bound, and my copy is now in pieces. No texts, all history (very concisely written) and the tunes. Excellent index. After about 30 years of searching I've found a very few that he doesn't have, but it wasn't easy. www.erols.com/olsonw for the ABCs. Most of the broadside ballad using the tunes are in the broadside ballad index there.