The body of work presented here makes a contribution to critically-informed research on management of Information Systems in their organizational contexts. An interpretive stance is taken, recognizing that people create their own perspectives of `realities' in context, through sense-making processes that are unique to them. A research agenda within a distinctive approach of Critical Systemic Thinking is elaborated. This is based in phenomenology and focuses upon individual uniqueness as a legitimate sphere of inquiry. Critical Systemic inquiries do not seek to generalise from the particular, but to gain a richness and depth of understanding. This is intended to enhance the dimension of transparency, rather than clarity in reflections upon unique phenomena: relevance in understandings, rather than rigour. Critical Systemic inquiry provides support for exploration of contextual factors in the experience of particular individuals, without losing a holistic, open systems perspective on complex problem situations. This perspective is applied in order to explore and critique the ideas and values underpinning practice in the fields of Information Systems and Knowledge Management, and in particular IS strategies. Two alternative paradigms within which information Systems may be conceived are contrasted. The impact of uncertainty inherent in dynamic organizational environments is explored. In particular, ways in which individuals approach dealing with unstructured problem spaces are subjected to inquiry. An observed desire to simplify complex decision spaces is problematised in the discussion. The dangers inherent in breaking down such spaces are highlighted and an approach that embraces uncertainty is advocated instead, through exploration of specific learning cases. These cases are used to illustrate how paradoxical thinking can inhibit effective practice. It is suggested that problem spaces may best be resolved through creation of productive learning spirals, in which all engaged stakeholders are encouraged to participate. This work suggests that practice can be improved by giving greater recognition to individually-unique understandings of context held by different engaged stakeholders. Furthermore, approaches to decision-making that embrace uncertainty are suggested to be more effective than those that seek to simplify, ignoring the inherent complexities of organizational life. Difficulties in applying complex, open systems methods such as those described within constraints of time and resources are recognised. Suggestions for dealing with these challenges are put forward and illustrated, through identification of constitutive rules for Critical Systemic Thinking as a basis for evaluation.