Currently, there are many perspectives aiming to account for what the field of information systems (IS) is or should be. For some, IS is conceived as a reference and stable discipline with dominant or core knowledge to export to other disciplines. To others, IS still requires a more eclectic/fluid perspective to enable IS to be adaptable to emerging challenges and possibilities. In both types of perspectives, there is a need to appreciate fully how IS knowledge has effectively unfolded through time in broader contexts of social sciences. In line with an emerging research orientation to conceive the IS field as both dominant and eclectic, we propose a systemic framework to account for these stages. We identify key IS knowledge concepts/themes emerging from analysing 4100 abstracts from articles in eight IS journals covering European Union/US regions over the last 25 years. Our findings suggest that such knowledge does not accumulate, but rather, some IS key concepts like systems, information and use resurface over time, leading to draw important implications for IS education, research and practice.