This volume emerged from a very ambitious and successful international symposium sponsored by the Chicago Heart Association in March of 1958. Half-day sessions were devoted to formal presentations and informal discussion dealing with (1) physiology, (2) pathology, (3) the pulmonary circulation in primary lung disease, (4) the pulmonary circulation in congenital heart disease, and (5) the pulmonary circulation is acquired heart disease. There were thirty-four official participants, including seven from abroad; in addition there were, among an audience of eight hundred, many other distinquished contributions to this area, some of whom participated in the discussion. Although much of the visual material presented (including many elegant color photographs) could not be included in this volume, the "Pulmonary Circulation" is a very skilfully edited work which brings to the reader the formal presentations in their entirety and all of the meaningful discussions with its original flavor. This volume is recommended as a