Ulf von Euler devoted his life to searching for the chemical signals that control physiological processes. In a career spanning six decades and during which he published four hundred and sixty-five scientific papers, von Euler achieved remarkable success. While still in his twenties, he discovered both substance P and prostaglandin, two important compounds that have since been studied extensively. Prostaglandins have become valuable to doctors for the treatment of many disorders, and may be used to treat blood pressure problems, infertility, peptic ulcers, and asthma. Martin A. Wasserman, in American Pharmacy, wrote on the significance of prostaglandins to modern medicine, stating that "Prostaglandin' signifies more to scientists today than any medical term since cortisone. For millions of people around the world, prostaglandins hold the promise of relief from an extraordinary range of physical discomforts and life-threatening illnesses." In addition, von Euler became the first person to isolate and...