A study investigated the effects of text processing orientations and reader-generated versus text-based comprehension aids on readers' comprehension of expository text. The processing orientations included memory-oriented processing, organization-oriented processing, understanding-oriented processing, and a read and study control. Subjects, 136 undergraduate students, read an expository passage and engaged in one of the four processing approaches through either reader-generated or text-based activities. Following a 24-hour delay, students' learning was measured by memory measures, organization measures, and an understanding measure. Results indicated that processing orientations yielded different degrees of knowledge about the passage. Readers processing the text in the memory-oriented mode recalled significantly more on the memory measures than readers in the understanding-oriented processing. Similarly, readers processing the text in the organization-oriented processing mode performed significantly better on the organization measures than readers in the other processing orientations. Readers in the understanding-oriented processing mode did not, however, show significantly superior performance on the understanding measure. Readers using text-based comprehension aids for each processing orientation performed significantly higher on each of the outcome measures than readers generating their own comprehension aids for each processing orientation. Findings suggest that teachers should determine a reader's amount of prior knowledge on the reading topic before encouraging the reader to engage in a generative activity; and the way students read and study text information affects the way they comprehend and recall. (Three tables of data are included. Contains 30 references.) (Author/RS)