An understanding of the importance of various risk factors, the pathogenesis of myocardial ischemia, and the appropriate use of various noninvasive and invasive tests is essential for management of patients with known or suspected coronary artery disease (CAD). Although coronary angiography remains the "gold standard" for diagnosis of CAD, much of the data obtained from risk factor assessment, medical history, and various noninvasive tests provides information that may be even more important than cardiac catheterization data alone for defining prognosis and directing management.