Since the early days of compulsory school, printed textbooks have been the main medium of instruction and content delivery in classrooms across the world. However, in step with the digital revolution, the way knowledge is mediated as well as classrooms as a whole have undergone substantial changes. They have developed into complex and dynamic learning environments where information is mediated through a variety of channels. Previous research shows that blended learning environments can have a positive effect on students’ learning outcomes. However, it has also been found that technology and digital resources have to be integrated properly. If used in an unstructured way, they can inhibit learning. This thesis aims at investigating how educational publishers adapt their formats and contents to these changed learning environments and the needs and challenges that arise in connection to the changes. The investigation is conducted as a case study at a Swedish educational publishing company which develops so-called blended textbooks, i.e., printed textbooks complemented and enhanced with multimodal digital learning resources mediated via an interactive platform. The case is investigated through an information architecture lens, applying the context, content, user model as theoretical framework. In order to investigate the complex interplay between context, content and users in the development of blended textbooks, this study follows a mixed-method approach, including qualitative interviews, a heuristic evaluation and the collection of quantitative web analytics data. The results of this study show that the blended textbook format has potential to support teachers and enhance student learning in modern classrooms. A combination of printed book and digital resources was shown to provide structure and continuity in complex, information rich environments. At the same time, the flexibility and adaptability of the format to different student needs can enhance learning and reduce teachers’ workload. For educational publishers this implies that traditional organizational structures have to be re-thought. The development of blended textbooks is more fast-paced and requires cooperation in multidisciplinary teams. In order to meet teacher and student needs a user-centered approach to developing blended textbooks should be applied. It has been shown that web analytics data could facilitate monitoring user behavior and identifying needs. However, the personal contact with users must not be neglected.