Growing interest in universal preschool education has prompted researchers to examine the potential costs and benefits of making high-quality preschool available for all children one or two years before kindergarten entry. The analysis reported in this document builds on a previous RAND study which estimated that a high-quality, one-year, voluntary universal preschool program in California would generate $2.62 in benefits for California society for every dollar of cost (Karoly and Bigelow, 2005). Assuming that 70 percent of each year's group of eligible 4-year-olds participate in the program (approximately 385,000 out of 550,000 children), the study estimated that California society would receive $2.7 billion in present-value net benefits. (Contains 12 tables and 8 figures.) [This report was prepared for The David and Lucile Packard Foundation by RAND Labor and Population, a unit of RAND Corporation.]