This article considers the role of reader characteristics in processing and learning from informational text, as revealed in think-aloud research. A theoretical framework for relevant aspects of readers' processing and products was developed. These relevant aspects included three attentional foci for processing (comprehension, monitoring, and evaluation) and five types of processing behaviors (use of strategies, metacognition, monitoring, goal setting and pursuit, and use of prior knowledge). Relevant aspects of products included mental representations of text (textbase, situation model of text, situation model of phenomenon, and author model) and the quality of those representations. A body of 45 studies was identified, considering reader characteristics of ability, experience, knowledge, and interest. Overall, low levels of all these were associated with an emphasis on local-level processing and effortful construction of a textbase, whereas higher levels were associated with more globally directed, more effective, more flexible engagement, leading to better quality mental representations and greater learning. (Contains 1 figure.)