This paper reports on a longitudinal multiple case study of SAP sites carried out between 1999 and 2002 on the use of e-business applications with existing ERP systems. A comprehensive research framework based on structured case studies was developed for this study. This framework used three different models at various stages of research to give a multi-faceted view of each case. The combined application of case methods by Carroll et al. (1998), Klein and Myer (1998), and Eisenhardt (1989) is proposed as an appropriate method for maintaining a balance between research rigour and relevance. This composite case-based method provides a structured, yet flexible and dynamic approach to case study interpretive research. Other researchers are urged to apply similar multi-viewed analysis.