The Number Four school is a centralized early childhood center in the Lawrence Public Schools, Nassau County, New York. Implemented in September 1982, a full-day kindergarten program was developed by staff and administration to expand and enrich the curriculum and program horizontally while maintaining the original half-day program's developmental and child-centered philosophy. This report discusses added program components, including in-depth and integrated curriculum themes, additional trips, an expanded cooking and nutrition program, increased language development and language experience opportunities, expanded "prereadiness" computer activities and programs, and other enrichment factors. The report also addresses changes and refinements made during the second year of implementation; the evaluations of parents, staff, and administration; standardized testing; the advantages of a full-day kindergarten program; continuing problems and concerns; and recommendations for future consideration. On the basis of evaluations cited in the report and data included in the appendices, evaluators postulated that the program may have important implications for ensuring equity in education for less advantaged children. Appendices provide a report and summary of home visits; results of full-day kindergarten/first-grade Follow Through evaluations; results of the Hammondsport Assured Readiness Program; summary and recommendations of staff evaluation of full-day kindergarten; and related evaluation forms and graphs. (RH)