One peculiarity of relationship marketing is that the pioneers drew to some extent on theory; the motivation behind relationship marketing being rooted in empirical observations and managerial problems, which highlighted the value added of relationship-based managing. The perception of these issues led the pioneers to challenge established, mostly transaction based theories on the market and marketing. Early contributors, such as Arndt, perceived relationships as attempts to domesticate the market. Currently research is moving its focus to the economic value of relationship based managing. A major objective of this e-book is to provide a forum for the discussion and further development of relationship theory.