Handbook for Modal Counterpoint

From Preface: "...It is the technical foundation of the sixteenth-century style that the authors of this Handbook have undertaken to present in a form explicit enough for a first approach to the subject. To lay this foundation, they have adopted the time-honored method of the Cantus Firmus and Five Species. True, the Cantus Firmus was no longer in general use in sixteenth-century composition; but it was still the basis of the method by which those composers learned their craft, and it must have shaped their thought as well as their technique. In retracing the steps of those learners, the present-day student may come to share that thought, to sense the spirit behind the tangible elements of the style...."