""Gregorian Accompaniment: A Theoretical and Practical Treatise upon the Accompaniment of Plainsong"" is a book written by Louis Niedermeyer and published in 1905. The book is a comprehensive guide to the art of accompanying Gregorian chant. It covers both theoretical and practical aspects of the subject, including the history of Gregorian chant, the principles of harmony and counterpoint, and the techniques of accompaniment. The book also includes numerous examples and exercises to help readers develop their skills in this area. Overall, ""Gregorian Accompaniment"" is an essential resource for anyone interested in the art of Gregorian chant and its accompaniment.""This scarce antiquarian book is a facsimile reprint of the old original and may contain some imperfections such as library marks and notations. Because we believe this work is culturally important, we have made it available as part of our commitment for protecting, preserving, and promoting the world's literature in affordable, high quality, modern editions, that are true to their original work.