The paper describes the application of a computer-assisted writing program in a special high school for learning disabled and dyslexic students and reports on a study of the program's effectiveness. Particular advantages of the Macintosh Computer for such a program are identified including use of the mouse pointing tool, graphic icons to identify available options, menus, windows, the high resolution screen, and standardization of software applications. The study evaluated use of the computer with 27 students who spent one class session a week in the Computer Aided Writing Project. Comparison of pre-testing (September) and post-testing (May) showed mixed results. Further analysis of results indicated a distinction between active/expressive tests or tests couched in the context of a full paragraph, and passive/receptive tests or tests of tasks isolated from context. All the improvements students made were in the active, paragraph-size tasks: organizing specifics into paragraph form, proofreading, writing/grammar, and speaking/grammar. Students' performance on tasks isolated from paragraph context (crossing out unrelated specifics in lists, categorizing/outlining items in lists) and the receptive tests of reading/grammar and listening/grammar showed no improvement and in some cases showed some loss. Teacher observations tended to be positive. (DB)