This paper describes the current state of research on Success for All, a program built around the idea that every child can and must succeed in the early grades. Success for All assumes that every child without organic retardation can read. Requirements for success include prevention and intensive early intervention. Success for All began in one Baltimore (Maryland) school in 1987-88 and has spread to about 300 schools nationwide in fall 1995. Almost all Success for All schools are high-poverty Title I schools, and the majority of programs are schoolwide programs under Title I. To summarize the outcomes of the program in all schools and all years involved in experimental control comparisons, this paper uses multi-site replicated experiment analysis in which each grade level cohort is considered a replication. Evaluation results for 19 Success for All schools in 9 districts in 8 states clearly show that the program increases reading performance. Of particular interest are results that compare Success for All with Reading Recovery for different purposes. Results demonstrate that comprehensive, systemic school-by-school change can take place on a broad scale while maintaining the integrity and effectiveness of the model. (Contains 6 tables, 6 figures, and 39 references.) (SLD)