A new model of the revision process in written composition, based on the results of thinking aloud protocol studies, is presented in this report. The report begins by discussing earlier observations and theories of revision that establish four points: (1) there are large differences among writers in the amount of revising they do, (2) expert revisors attend to more global revising problems than do novices, (3) writers have more difficulty detecting faulty referring expressions when revising their own text than when revising the texts of other writers, and (4) the ability to detect text problems appears to be separate from the ability to fix these problems. The report then describes the model according to the following central subprocesses: task definition, evaluation for problem detection and diagnosis, and strategy selection. The report concludes with a detailed discussion of the protocol data on which the model is based. References, tables of data, a sample revision task, and an explanation of talk-aloud protocols of the revision process are appended. (HOD)