This small volume is not a treatise on the relation between heart disease and tuberculosis. The subtitle, "Efforts, Including Methods of Diaphragmatic and Costal Respiration, to Lessen their Prevalence," explains the author's purpose. The theme is the system of respiratory exercises which Knopf claims has great value in the prevention and treatment of these conditions. The evidence is presented largely in the form of quotations from authorities more or less familiar with his ideas. The arrangement of the book lacks system, and on the whole it is sketchy and loosely written.