This paper presents lessons learned from an action research venture involving a network of SMEs and a group of IS researchers. The purpose is to discuss some fundamental methodological issues that we learned when doing action research with a network of interrelated organizations, rather than report the action research project itself. Our results are presented as four dualities that should be addressed throughout diagnostic and therapeutical activities in a network action research project. The dualities (teach–learn, local–global, multifaceted–unified, and liquid–crystal) are forwarded as analytical scaffolds to cope with the inherent difficulties of understanding and acting in IS action research projects, especially network action research.