From the very first moment action research started to be used in the social research field until now, it has presented significant variations. Action research looks like a mosaic of theoretical and methodological approaches, named differently from time to time and/or from place to place: for example, practitioner inquiry, practitioner research, teacher research, participatory action research, and so forth. The basic aims of this article are to find the reasons for this and to discuss the implications of the phenomenon. Starting with the first issue, we could ask ourselves: why do we today find so many and considerable variations in action research approaches in the literature? The evident reason is because action research draws upon many theoretical paradigms that--in some circumstances--are not only different, but also contradict each other. Hammersley states characteristically that action research draws upon positivism, pragmatism, hermeneutics, critical theory and postmodernism! After such claims, we can easily wonder: how can such a multi-paradigmatic approach compose cohesive methodological proposals? We can also pose another crucial question: although we can easily understand that this multi-paradigmatic nature is a real advantage which gives action research a pluralistic essence, is it really "a strong indicator of the power of action research to reinvent itself according to local needs" as Somekh stated, or might it at the same time conceal serious risks?