An excerpt from the Introduction:
COUNTERPOINT is the art of so writing two or more melodies that they may be satisfactorily performed at the same time. All weaving together of melodies, from the simplest combination of two simple themes to the most complex polyphony of a Wagner score is Counterpoint. But the study of Strict Counterpoint (our present object) resolves itself into building one or more melodies upon a given melody. The added melody or melodies may be above or below the given melody.
Counterpoint was the earliest form of artistic musical composition. It was the outgrowth of the simplest attempts of two singers to sing together without producing discordant effects. In Counterpoint then, we are primarily concerned with the movement of voices or parts, and the student should endeavor from the beginning to accustom himself to follow each part in its movement, to think, so to say, horizontally, instead of thinking as in Harmony, perpendicularly. It is to be remembered too, that Counterpoint is primarily a series of consonances, dissonances being introduced only under careful restrictions.
There are three most important principles to be observed in all writing of Counterpoint.
First, the Principle of Variety, by which is meant that the constant aim of the writer of Counterpoint is to avoid monotony, no matter from what cause it may arise. Thus broken chords and arpeggios as suggesting rather a single harmony than several melodic tones; voices moving a third or a sixth apart, by which one voice is merely a copy of the other; repetitions of figures; sequences, and nearly stationary parts are all undesirable.
Second, the Principle of Clearness. Nothing must be introduced which would tend to obscure the movement of each voice or confuse one voice with another voice, or to give the Counterpoint the effect of aimless wandering. Fig. la. Thus, crossing or overlapping of parts, voices moving out of their proper range (Fig. 16), and formless melodies are all to be avoided.
Third, the Principle of Euphony. One important function of music is to please the ear, and although the pleasure derived from fine Counterpoint is of a different character from that which we get from beautiful Harmony, still the composition must always be well-sounding.
As Counterpoint deals chiefly with melodies, the student should write his Counterpoint as if for voices, keeping within the range of the voice for which he is writing and observing the following suggestions as to the progression of each voice or part.