This thesis explores ideas as a type of product. Specifically, it investigates the thesis that the marketing of ideas is a demonstrably unique sub-field of the marketing discipline. Ideas marketing literature provides limited theoretical grounding from which to answer this question. Therefore, an understanding of ideas was sought by studying those who work with idea offerings on a daily basis. Three organisations involved in marketing ideas were investigated: The Health Funding Authority, marketing the idea of non-discrimination against people with mental illness; the Peace Foundation, marketing the idea of peace; and a Buddhist Meditation Centre in relation to marketing Buddhism. A fourteen-month study, drawing on a range of ethnographic techniques from participant observation to one-on-one interviews, was conducted with these three case organisations. The findings reveal eleven themes regarding idea offerings. These themes are analysed in order to establish the conceptual domain of ideas. This conceptual domain can be summarised through five descriptors: immateriality, interminability, omnipresence, transferability and Weltanschauung. Each of these characteristics is considered relative to goods, services and social products. In so doing, the distinctiveness of ideas is demonstrated. The five characteristics of ideas form the basis for establishing the marketing of ideas as a unique sub-field of the marketing discipline. The contribution of this thesis for the marketing discipline is both conceptual and theoretical. This research highlights the need to distinguish idea offerings semantically from ideas that are connected to other aspects of marketing activities. The research findings also raise questions about the applicability of some marketing theory to ideas, in particular the exchange paradigm. The mix of incongruity and applicability of marketing theory in the context of ideas imply ideas are situated on the edge of marketing’s domain.