The following text attempts, without pretending completeness, to analyze approaches to action research based on where and how they position themselves socially, on how they work, and on their actual basic distinctions. The result is a tentative typology presented roughly historically, which cuts through the many labels typical of current action research. Different approaches are useful, each for different purposes. Still, most circle consciously or subconsciously around some form of “practice” which works as a standard of measurement or quality criterion. The conclusion is that there is a certain sine qua non in the field of action research, i.e. a form “toward which, ways of doing things tend to evolve from a wide variety of starting points”.