The Computer Assisted Spanish English Transition Sequence (CASETS) Project used a developmental research approach to design and adapt curriculum materials for computers; the approach involved a continuous process of materials design, classroom implementation, evaluation, and modification. During the first year of the project, sets of 26 lessons each were designed for first and second levels of English as a Second Language (ESL) classes and seventh and eighth grade social studies and life skills classes. Materials were written in BASIC programming language for use with a TRS-80 II computer and video screen. First-year evaluation results, based on data collected through site visits, interviews, and project office records, indicate that CASETS was successfully implemented as proposed during the 1980-81 school year. The desired English language proficiency criterion was achieved, and surveys of parents, students, and teachers indicated a strong positive attitude toward the project and computer assisted instruction (CAI). Additional capabilities of the project were planned for implementation during the 1982-83 school year. The project includes a training component for educators and administrators and for CASETS project staff. A glossary of CAI-related terms is attached. (LMM)