We described a formative evaluation of Tectonica Interactive, an introductory geology hyper-book that was authored and delivered using the MetaLinks software. MetaLinks is a framework and authoring tool for the creation of adaptive hypermedia documents that support the learner's exploration of richly interconnected material. The formative evaluation involved 19 subjects, and data was collected from navigation traces, a questionnaire, focus-group discussions, and think-aloud interviews. We interpret the results in terms of how the system addresses the issues of disorientation, cognitive overload, discontinuous flow (poor narrative flow or poor conceptual flow), and content non-readiness. We were interested in how features of the current implementation address these issues, and we were looking for evidence for the need of more advanced (adaptive and/or intelligent) features.