Osvaldo Marrero (Osvaldo.Marrero@villanova.edu) earned degrees from the University of Miami and from Yale, where he was also a postdoctoral research fellow. Subsequently, he completed courses at the University of Minnesota and at the Université de Montréal. He has worked in industry and academia, including affiliations with mathematical and medical groups at several universities. He has been a researcher in several units of Yale University’s medical school and served as an adjunct professor of pediatrics at the University of Pennsylvania. For many years, he has been a professor at Villanova. He has published papers in epidemiology, mathematics, medicine, and statistics. He’s known for mathematical work on combinatorial designs and related structures, and for statistical work on seasonal variation in epidemiological data. He has presented at professional meetings worldwide and delivered invited lectures at universities in the Americas and in Europe. When not working, he pursues other passions, too numerous to mention.