In this month's issue of The Journal of Clinical Hypertension, we highlight another hypertension icon. Dr. Suzanne Oparil is a clinical cardiologist who has been involved in the investigation of some of the fundamental mechanisms of vascular disease. Information derived from her studies has been used to develop specific treatments for hypertension. Dr. Oparil was one of those few women who attended medical school at a time when most of the students were males. She graduated at the top of her class at Columbia University College of Physicians and Surgeons and trained at Columbia and the Massachusetts General Hospital. She was on the faculty of the University of Chicago until 1977, when she transferred to become Professor of Medicine,Physiology, and Biophysics at the University of Alabama at Birmingham, where she has continued her research. Early in her career, Dr. Oparil observed that angiotensin-converting enzyme (ACE) was capable of generating a vasoconstrictor hormone, angiotensin II. Her work, along with that of investigators at the Massachusetts General Hospital and other institutions, led to the development of ACE inhibitors. Initially, Dr. Oparil's interest was focused on the pulmonary circulation. She identified endothelin as a major mediator of pulmonary hyper-tension and as a potent vasoconstrictor. In recent years, she has been investigating novel pathways by which estrogens protect against vascular injury. Her work has led to important clues about how female sex hormones protect blood vessels. Throughout her career as a basic scientist, Dr. Oparil has also maintained a clinical interest. She has been involved in numerous hypertension clinical trials with different medications. She served as President of the American Heart Association and was the first woman president of the American Federation of Medical Research. Dr. Oparil has always been an outspoken critic of those in medicine who speak to hear themselves heard. She has been a strong advocate of approaches to treatment that may not have been popular. Throughout her career, she has combined scientific judgment with stern clinical discipline. Her contributions to the understanding of hypertension have been significant.