This report examines the theory that when people understand a text, they create a complex scenario (or model) within which the events described might plausibly occur. In order to study construction and revision of such models, five subjects were given difficult-to-understand texts, and were later asked to discuss the processing they went through to make sense of the text. The results indicated that skilled readers use a variety of strategies for revising and evaluating different models, finally converging on a model that best accounts for the events described in the text. Protocols are used to describe specific strategies used in constructing an initial model of the text, revising the model, and evaluating the model. The report concludes that pinpointing the strategies that skilled readers use for dealing with difficulties in understanding will help to specify the strategies which unskilled readers must learn. (AA)