In the preface to the first edition of this book, the author states that his purpose is to describe the criteria on the basis of which the diagnosis of diseases of the lungs and the heart can be established by roentgenologic methods and to make available a large, varied collection of radiographs that illustrate both the common and the rare conditions in which roentgenologic examinations may be of value. In the four years since the publication of the first edition, numerous diagnostic criteria and techniques have been evolved. The author attempts to incorporate all of the significant advances in the second edition, and certain sections are entirely new. Others have been partially rewritten and enlarged. The illustrations have been improved and increased in number. The section on congenital heart disease has been greatly expanded to include data on cardiac catheterization, angiocardiography, and other modern methods of clinical and roentgenologic diagnosis.