Computer assisted instruction (CAI) in Biology and Developmental Reading was administered at two junior high schools and two senior high schools in Philadelphia. The achievement of the students in CAI was compared with comparable students in traditionally instructed classes. The results of the standardized tests were equivocal. In Reading, the CAI classes performed significantly better than comparable students in traditional classes. Differences in achievement were not obtained between the CAI and traditional Biology classes. This was attributed to computer down time and a lack of sufficient content validity in the standardized Biology test. An attitude survey constructed for the project indicated that the pupils liked working with the machines, but were frustrated when the system did not function properly. A discussion of the project, including the results of unstandardized achievement tests, and an analysis of the pupils' responses while interacting with the computer is included. Tables of statistical data supplement the report. The appendix contains a list of topics covered in the CAI units and samples of the student and teacher questionnaires. (Author/JY)