Alternative computer input devices are a critical component of the important role computer technology plays in meeting the needs of individuals with disabilities or other challenges. In February 1992, a special alternative computer keyboard, IntelliKeys, was given the coveted first prize in The Johns Hopkins University National Search for Computing to Assist Persons with Disabilities. Results of the Phase I Small Business Innovation Research (SBIR) study by the creators of Intellikeys establish the technical basis for the development custom overlays for IntelliKeys, a new set of educational tools that has as its purpose increasing the accessibility of computers and computer software for individuals with disabilities. The research objectives of the Phase II study focus on (1) identifying the characteristics of effective custom overlays; and (2) developing and testing materials based upon those characteristics, including custom mathematics and science overlays; mathematics and science Curriculum Activity Booklets; and a teachers' "how-to" manual so that teachers will be able to create their own curriculum-based custom overlays that will be of maximum benefit to each particular student. The project will make an important contribution to the mandate of Public Law 94-142 which stipulates that to the greatest degree possible students with disabilities should have access to educational opportunities equal to those of their able-bodied peers.