This thesis aims to investigate how the experience of engagement in interaction can be explained by examining the experiences of richness and control and how these experiences are influenced by the features of a product, the expertise of a person and the type of task. This research is carried out within the domain of digital products. From the results of these investigations a conceptual framework will be created that is intended to assist interaction designers in the creation of engaging interactions and may also be used to guide the development of user-models for product intelligence.