Selective coronary arteriography has become an unusually useful technique in evaluating patients with known or suspected ischemic heart disease. The contribution of F. Mason Sones in developing the technique and in emphasizing that properly performed studies in experienced hands can be done at an acceptable risk cannot be overemphasized. Although the study can give information only on the anatomical aspects of the disease, it has remarkably broadened ouo understanding of the whole spectrum of coronary arteriosclerosis and ischemic heart disease. This is related to the fact that the method has provided the opportunity to study an extraordinarily large number of patients representing virtually every clinical subset of the disease. The importance of nonanatomical factors, better prognostic information about the disease, and more complete understanding of the hemodynamic ocrrelates and mechanisms of drug action have resulted from investigative studies using coronary arteriographic methods. Because ischemic heart disease is such a complex and variable entity, it is important to stress that coronary arteriography and left ventricular angiography can provide only anatomical information, and that the method has significant but ordinarily recognizable limitations. Some of these limitations are technical and are not important considerations in experienced hands in well-run laboratories. Other problems are inherent in the anatomical complexity of the disease and the coronary circulation. Hence, appropriate emphasis on the details of the patient's history, including risk factors and age, as well as other selected clinical laboratory studiies, such as exercise electrocardiography, are important in assessing the patient's total problem. Because of these factors, the greatest value of coronary arteriography is realized when it is performed as part of a thoughtful, detailed--and highly individualized--evaluation of the patient.