Understanding the experience of a user during information interaction is recognized as a grand challenge for the development of information systems. Yet, in parallel, it is this challenge that is mostly left ignored. Through three studies, this thesis makes the IX -- the experience while interacting with information -- a manageable concern for information systems. First, an IXf is introduced that transforms the fuzzy concept of the IX into a formalized one. The IXf models the relation between relevance and IX. It shows how characteristics of information direct a user's affective responses and how a user's state can influence judgments of information. Second, a computational model of textual complexity is developed. The model is founded on findings about the causes of processing difficulty that a reader experiences while reading a text. This novel approach offers a unique model that is both able to distinguish texts according to their textual complexity and to predict users' appraisal of the complexity of a text. Third, a user study is conducted that explores the determinants of the emotion of interest. Using the model of textual complexity, the existence of a "sweet spot" of interest was confirmed; that is, interest peaks where the information is complex yet comprehensible. In line with this finding, the relation between the objective textual complexity of and interest in text provided unique proof for the existence of the Wundt-curve (which shows an inverted-U shape) that was posited over a century ago. Together, this series of studies shows how and confirms that information systems can orchestrate an IX: by adopting the IXf and appreciating when complexity becomes interesting.