"Richard Hoppin's discussion of medieval music ranges from earliest chant of the Roman Church to polyphony in the beginning of the fifteenth century."...from the DJ
So a music nerd's book of books on period music, most helpful for me in putting an historical perspective on the music of the times of olden days... seriously the church modes had a great illustration and key to understanding the relationships between Dominants, Finals, and penta and hexa chords. like many texts on early music what we don't know and it seems never will get to the bottom of is perhaps more interesting, but still pleanty of disembodied words carefully decribed int the text to decribe the mysteries of this art period.
Very complete book about medieval music, with lots of information about sacred music of that Age. Very usefull references to other authors and works about the subject.