Learning about conceptually-rich domains with open-ended computer-based learning environments (CBLEs) such as hypermedia involves a complex set of interactions among cognitive, metacognitive, motivational, and affective processes (Azevedo, 2005, 2007, 2008; Graesser, McNamara, & VanLehn, 2005; Jacobson, 2008; Moos & Azevedo, in press; Vollmeyer & Rheinberg, 2006; Zimmerman, 2008). Current research from several fields including cognitive and learning sciences provides evidence that learners of all ages struggle when learning about these conceptually-rich domains with hypermedia. This research indicates that learning about conceptually-rich domains with hypermedia is particularly difficult because it requires students to regulate their learning. Regulating one’s learning involves analyzing the learning context, setting and managing meaningful learning goals, determining which learning strategies to use, assessing whether the strategies are effective in meeting the learning goals, evaluating emerging understanding of the topic, and determining whether there are aspects of the learning context which could be used to facilitate learning. During self-regulated learning, students need to deploy several metacognitive processes to determine whether they understand what they are learning, and perhaps modify their plans, goals, strategies, and effort in relation to dynamically changing contextual conditions. In addition, students must also monitor, modify, and adapt to fluctuations in their motivational and affective states, and determine how much social support (if any) may be needed to perform the task. Also, depending on the learning context, instructional goals, perceived task performance, and progress made towards achieving the learning goal(s), they may need to adaptively modify certain aspects of their cognition, metacognition, motivation, and affect.