Every jittery Vineyard beachgoer is familiar with the iconic image of the restless great white patrolling the shallows, mouth agape, in search of a fleshy excuse to close it. Stacks of shark books celebrating the more lurid aspects of their behavior, particularly their extremely rare propensity to attack humans, already fill library shelves, but in Demon Fish, Washington Post environmental reporter Juliet Eilperin makes the case that the more fearsome animal is in the mirror.