Counterpoint Books Theory Things   William Wieland
Popular counterpoint textbooks today include the following:
  • Kent Kennan's Counterpoint, based on eighteenth century practice. (1959/1972)
  • Robert Gauldin's A practical approach to sixteenth-century counterpoint (1985)
  • Robert Gauldin's A practical approach to eighteenth-century counterpoint (1988/1995)
  • Harold Owen's Modal and Tonal Counterpoint (1992)

Knud Jeppesen's Counterpoint (1931) was an important text of the last century.

Johann Joseph Fux's Gradus Ad Parnassum (1725) was the groundbreaking counterpoint book. Haydn, Mozart and Beethoven (Viennese Masters) all studied from this book. Alfred Mann translated and edited it in 1943.
From the back cover of the inexpensive Mann paperback:

The most celebrated book on counterpoint is Fux’s great theoretical work Gradus ad Parnassum. Since its appearance in 1725, it has been used by and has directly influenced the work of many of the greatest composers. J. S. Bach held it in high esteem, Leopold Mozart trained his famous son from its pages, Haydn worked out every lesson with meticulous care, and Beethoven condensed it into an abstract for ready reference. An impressive list of nineteenth-century composers subscribed to its second edition, and in more recent times Paul Hindemith said, “Perhaps the craft of composition would really have fallen into decline if Fux’s Gradus had not set up a standard.”