The primary purpose of California's Birth Through 3 Program is to increase the number of the most vulnerable children receiving high quality comprehensive services that meet their needs for early learning, health and family support. This paper details the program's purpose and design, and concludes that the proposed enactment of the Kindergarten Readiness Act of 2014 creates a rare opportunity to redirect $175 million in savings from current expenditures for four-year-olds to improve and expand early learning and care services for a younger population of children with the highest needs and the most to gain.