Causal reasoning is central to scientific practice and to everyday life, yet has received scant attention in Information Systems epistemology. This essay identifies six types of causal analysis that can be used in IS research: regularity, counterfactual, probabilistic, manipulation, substantival (mental), and enabling condition analysis. A framework is developed for application of the different types of analysis in terms of two dimensions; planned versus emergent systems and prescriptive versus descriptive modes of research. It is shown how the different types of analysis can be used in each cell of the framework. The identification of the substantival and enabling condition types of analysis for Information Systems research is novel. Further work is indicated, particularly with respect to probabilistically necessary and sufficient conditions, qualitative evaluation of causal chains, and the plausibility of claims for causality with some statistical methods in common use.