This work, dedicated to him in the last days of his life, was conceived as the faithful interpretation of his perfect and rare singing. For over a decade and a half, I had the privilege of associating with the great artist, not only in the capacity of medical adviser but in the intimacy of a wonderful friendship, and his singing was to me a constant guide and inspiration in my investigations of the many problems of the human voice and vocal art. By closely observing his method of singing, I saw the correct application by the master himself of the natural laws governing the mechanism of voice pro duction, and I had the opportunity, by testing his ideas and principles, of ascertaining that they con formed with those I have developed in the scientific part of this book. As a modest wreath of admiration and friendship I lay this work on the grave of the great artist.