Willard Van Orman Quine (1908-2000) was probably the most influential American philosopher of the twentieth century. In Trading Ontology for Ideology Lieven Decock offers an insightful analysis of the development of Quine's ontological views from his first texts in the early thirties onwards. The importance of Quine's work in logic and set theory for his ontology is highlighted. Decock argues that the tenet of extensionalism is at least as important as naturalism, and assesses the relation between the two. The other focus of the work is the relation between ontology, i.e. what there is, and ideology, i.e. what can be expressed by means of words. Decock shows that the interplay between ontology and ideology is far more complicated and interesting than has generally been assumed.