In 1905, Fr. Gregory Sunol, OSB, of the monastery at Montserrat in Spain, published the book that became the standard text for understanding how to sing Gregorian chant. It remains today the most thorough explanation of tonality, rhythm, and, especially, the Psalm tones, to appear yet in print. It is both pedagogically effective and theoretically definitive. Herein you find the most thorough explanation of how Solesmes came to set the standard for chant for the entire world. The book was expanded through numerous editions in Spanish and French, and the English translation by G.M. Durnford in 1930 is based on the sixth French edition.