Foreword “Make or buy?” The question about optimal sourcing is one of the oldest and most central questions of managerial economics. Consequently, the question about IT outsourcing has been an important research topic of the Information Systems discipline for the past two decades. The financial services industry also has a long tradition in IT outsourcing (ITO) with IT representing, besides people, the only “production facility” of banks. The cost structure of non-physical pr- ucts and services in the financial services sector relies heavily on fixed costs and, thus, holds high potential for the inter-organizational bundling of processes and achieving cost savings from economies of scale and skill. In this book, Dr. Beimborn advances the traditional academic view on IT outsourcing towards a sourcing network perspective. The complexity in this paradigm, which adds to the complexity of the traditional outsourcing research perspective and, furthermore, generalizes it to a business process outsourcing (BPO) perspective, consists in the fact that typically more than two parties will negotiate and that the roles of insourcer and outsourcer are not necessarily p- defined in advance. It is striking that in the otherwise generally mature outsou- ing literature the sourcing network issue has been almost completely ignored so far.