The cetology in Herman Melville's 1851 novel, Moby-Dick, is a running theme that appears most importantly in Ishmael's zoological classification of whales, in Chapter 32, "Cetology". The purpose of that chapter, the narrator says, is "to attend to a matter almost indispensable to a thorough appreciative understanding of the more special leviathanic revelations and allusions of all sorts which are to follow." Further descriptions of whales and their anatomy occur in seventeen other chapters, including "The Sperm Whale's Head -- Contrasted View" and "The Right Whale's Head -- Contrasted View".