Information systems research is still a young discipline that has not accomplished a coherent profile yet. Without emphasizing the necessity of one common profile, this report discusses a number of candidate profiles or cores of the discipline. Firstly, a recent proposal made by Weber will be evaluated. Weber argues that "deep structure phenomena" of information systems constitute the core of the discipline. Slightly different from Weber, this paper is based on the assumption that information systems research aims at concepts which support the design, introduction, use and maintenance of information systems that are suited to increase an organisation’s efficiency. Therefore essential inhibitors of successful automation will be identified. Against this background, the report describes and analyses three prototypical approaches to accomplish a higher level of automation in organisations: a reductionist, an inductivist, and a constructivist approach. While there is evidence that the constructivist approach is most effective - and therefore a favourite candidate to constitute the core of the discipline, it will be shown that it implies severe epistemological problems. It will be argued that there is hardly any straightforward solution to these problems. However, for the information systems discipline to establish a profile of its own, it has to accept them as a pivotal challenge.