Daniel C. Abel is professor of marine science at Coastal Carolina University in Conway, South Carolina. His research focuses on the physiology and ecology of sharks and rays, and he is the coauthor of several books, including Tooth and Claw: Top Predators of the World (Princeton). R. Dean Grubbs is associate director of research at Florida State University's Coastal and Marine Laboratory. He is a shark biologist and international authority on shark fisheries and conservation.