The paper related what has been accomplished during the past six years in the development of IPI Science at the Learning Research and Development Center, University of Pittsburgh. There have been three major accomplishments: (1) Goals for the program have been established, (2) The serious problems that face a group of curriculum developers attempting to individualize a science program have been identified. The problems are of two major types: (a) Those of a practical nature; e.g. How can science instruction be given on an individual basis to first graders who do not read? (b) Those of a philosophical nature; e.g. Is an individualized model of instruction compatible with the goals of science education? (3) Lesson materials and equipment for A and B Levels have been developed. Each Level comprises about one year's work in a system where a student has science for two 40-minute periods per week. Presented is a description of student progresses through various stages in a mainstream continuum. Once the necessary prerequisites are mastered, the student begins work in the A Level by taking a Mini-Placement Test. He continues through A and B Level mainstream units, taking only those lessons whose objectives he has not mastered on the various Mini-Placement Test. Alternative modes of instruction are available. (BR)