Book excerpt: This book provides an expert analysis of the theory of the marketing firm by drawing upon operant psychology, economic theory and marketing to argue that all firms exist in order to market. The authors explore the nature of bilateral interdependence and suggest a framework to analyse the collaborative and competitive mutually reinforcing relationships within which the firm acts. The Marketing Firm leverages the power of case study design to operationalise and test the central propositions of this nascent approach to the study of firm behaviour from an economic psychology perspective. The authors develop and detail an entirely appropriate methodology for operationalising and testing a number of propositions through the examination and analysis of comprehensive secondary data published by the UK Competition Commission. The findings clearly support the central propositions on firm action and provide valuable insights for expanding the theory of the marketing firm. The Marketing Firm will be invaluable for researchers interested in behaviour analysis and the theory of the firm and for post-graduate students in microeconomics, institutional economics, marketing and research methods.