This second book of the 'bel canto' series by author, Kendrick Jacocks, serves as a scientific reference to the first book on the subject of 'bel canto'. It takes the anatomical and physiological route to explaining why the 'bel canto' position achieves the timbres, calibration, and control native to it. The book proves the functional aspects of the nasalis (nose muscle system), and provides detailed descriptions of the paranasal sinuses: ethmoid, sphenoid, maxillary, and frontal, and their effect on tone quality. It explains chest tensions; the connection between the pelvic floor and mask in supporting the breath, and the chest position. The books explains how to use the muscles that open and close the tone, the importance of the relaxation of the spine, and explains resonance. The book provides anecdotes from such writers, artists and teachers as Giovanni Sbriglia, Joan Sutherland, G.B. Lamperti, Regine Crespin, and Manuel Garcia.