This digest provides an overview of the Head Start on Science (HSS) program which is designed to encourage the science literacy of preschool children in Head Start programs and to improve the capacity of Head Start teachers, assistants, and parents. The overall goal of the HSS program is threefold: (1) to broaden HSS participants' science knowledge and conceptions; (2) to enhance participants' ability to use scientific inquiry; and (3) to integrate the HSS program into the core curriculum. In addition to an overview of the program, the program research base is summarized, program components are described, findings of the project are highlighted, and implications of the project are discussed. (Author/DDR)