Much of the anguish and the elation in our lives begins with a glance, a kiss and then—a lifelong struggle to make sense of the verb to love. Patients have faith that their doctor can set a broken bone or offer pills to adjust their blood pressure. But poets, philosophers and psychologists alike have long seen love as intangible and nebulous, beyond our abilities to define. As one young man with whom I worked said, “I don’t think anyone has ever had any real idea about this love thing, and you don’t either.” Love is a many-splendored, mysterious thing. How, people wonder, can I or anyone else proffer advice on enigmatic matters of the heart?