Founded in 1964, Nonesuch Records was a budget label specializing in a then-unusual repertoire of chamber music, particularly that of the Baroque period. This turned out to be excellent positioning for the Baroque and Renaissance Music Revival of a half century ago. Nonesuch released albums by the score, introducing the record-buying public to sounds -- and composers -- that many had never heard, or heard of, before. This week, we'll listen to tracks from a dozen or so of these old Nonesuch albums. If you're of a certain age, maybe you have one or two of these records up in your own attic.