In 1993, Philip Kitcher published The Progress of Science, probably the most important work of the English philosopher and one of the most representative of the naturalistic current in epistemology. In opposition to traditional epistemologies, The Advancement of Science is an attempt to formulate a conception of the progress and rationality of science from the contributions of psychology and neoclassical economics. In this book, Pettinaroli makes an approach to this fundamental work and an inquiry into its scope and achievements. What are the assumptions that Kitcher's naturalism shares with the Legend's conception of progress and rationality in science? Does Kitcher's proposal represent an alternative to traditional epistemologies? Is it possible to reconcile naturalistic principles with traditional notions of progress and rationality? These are some of the questions addressed in this paper in order to introduce the reader to the major work of one of the most important philosophers of science of the last decades.