Just because e-commerce seems like a useful tool that may assist a small to medium enterprise (SME) do its business better, it does not necessarily follow that it will be adopted by this business. The implementation of an e-commerce system in an SME necessitates change in the way the business operates, and so should be considered as an innovation and studied using innovation theory. In this chapter we will argue that the decision to adopt, or not to adopt, a new technology, has more to do with the interactions and associations of both human and non-human actors involved in the project than with the characteristics of the technology. Information systems are complex socio-technical entities and research into their implementation needs to take account of this complexity. This chapter describes three case studies of adoption (or, in one case, of non-adoption) of e-commerce by small business. The chapter describes a research approach based on actor-network theory and innovation translation that we show can be usefully employed in many socio-technical situations involving technological innovation.