Most studies of market development have concentrated on the private sector. This paper, in contrast, focuses on the not-for-profit sector by analysing market development in the British public library sector. This paper firstly presents a summary of the nature and extent of marketing develop ment in the library services sector. The paper continues by addressing the issue of why some local authorities under take a high level of marketing activity, while others do very little. A wide range of potential influences on the degree of marketing activity, both at the macro and micro level, was empirically analysed. This study concludes that the level of marketing activity is highly influenced by both the range of services offered by the local authority and the presence of a marketing function within a specific organisation.