Traditional instructional materials such as textbooks contain significant educational content, but the navigational mechanisms to access that content are limited and, more importantly, not designed with learning in mind. To address this gap, we present the Adaptive Map, a novel organization and navigation tool designed to help students better understand large collections of information such as those found in textbooks. The tool promotes conceptual understanding by leveraging expert-generated concept maps, which have been shown to improve learning. In addition, to alleviate problems associated with visually processing large-scale concept maps, our design integrated information visualization techniques to increase usability and facilitate processing. To evaluate the approach, a prototype was developed and tested in an engineering statics class. A multiple case study methodology was used to explore how students used the tool. Results show that the tool promoted conceptual understanding by facilitating advance organizer usage and students' exploration of relevant prior content.