The first volume of a two-volume final report provides a thorough description of the rationale, development, content, and materials in the ISCS project. Chapter one examines the rationale for the project and the developmental procedures used, including underlying assumptions about junior high schools, students and teachers, and reviews the general approach to the instructional design and the developmental procedures employed. The second chapter discusses style: the format and page design, both intended to promote readability; cartoons used to get attention, raise questions and summarize key concepts; excursions, short departures from the "core" for remedial help or for in-depth study; and commercial editions. Chapter two also reviews in detail the program content sequence, which integrates the subject matter of science and the processes of science. Numerous evaluative studies of the ISCS program are reviewed in chapter three, and the strategy and activities for disseminating the project materials are presented in chapter four. (PR)