Sixteen courses were taught over a 2-year period at eight universities using Perseus, a HyperCard-based hypermedia information system that contains multimedia information about the Greek world, in order to examine how type of assignment influenced student perceptions about the Perseus interface and learning performance. Data collection methods included interviews, observations, automatic transaction logging, questionnaires, and document analysis. Initially, evaluation was mostly formative to provide feedback to the designers; the focus later shifted to summative results that addressed how Perseus affects teaching and learning. Assignments were classified as either directed (high instructor control), undirected (high learner control) or mixed. Those assignments that used both instructional types generally yielded better ratings; directed assignments yielded higher ratings for confidence, and undirected assignments yielded higher ease of use ratings. Additionally, performance ratings were correlated with interface effects, but not with frequency of use or previous computer experience. (Contains 13 references.) (AEF)