The author's thanks are due to the Austin Organ Company, the Bennett Organ Company, Dr. W. C. Carl, the Estey Organ Company, the Hook & Hastings Company, the Hope-Jones Organ Company, the Hutchings Organ Company, Mr. M. P. Moller, Messrs. J. H. & S. C. Odell, and the E. M. Skinner Company, of the United States; to Messrs. Casavant Frères, of Canada; to Messrs. J. H. Compton, W. Hill & Son, Dr. J. W. Hinton, Alfred Kirkland, John Moncrieff Miller, and Henry Willis & Sons, of England; to Dr. Gabriel Bédart, of Lille, and M. Charles Mutin, of Paris, France, for valuable data, photographs and drawings, kindly furnished for this book.