For playing with a second person (a lutenist would be nice) or in ensembles, I wouldn't want to be without Orlandus Lassus, songs without text, opus 13-24 (two parts); Tielman Susato, Dances from 1551 (mostly 4 parts); Petrucci's Harmonice Musices Odhecaton (mostly three or four parts - fun to read in the origianal notation, but available in modern notation); and - really wonderful - The Glogauer Liederbuch (mostly three parts - I only currently have a xerox copy in modern notation thanks to the generosity of a friend, but it can be obtained from a library, I believe).
I mention these (there are certainly many others) because as satisfying as learning and playing the solo lute literature is, playing part music with others provides its own unique rewards. I love both! I found enthusiastic players by attending a meeting of our local recorder society. Ned -- To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
