Effective implementation of new information systems (IS) is a central concern of practitioners today. Research on IS innovation and implementation success factors has been considerable, however mixed and often conflicting results characterise the state of our knowledge. This paper reviews the literature concerned with IS innovation implementation to identify major concepts and key issues requiring attention. Three inter-related concepts are identified in the literature - complexity, uncertainty and knowledge dynamics - that have not been considered as interacting processes in any previous work identified. An interactive process model relating these three concepts is proposed to address this gap, and in doing so provides a way for the implementation process for IS innovation to be better understood.