California's public-school system recently introduced another grade level, Transitional Kindergarten, as an opportunity to offer universal access to early education for all 4-year-olds. Elementary school teachers and administrators must be well prepared to support and education these young children. This dissertation focuses on four key principles to ensure high-quality learning: Developmentally Appropriate Practices, Social and Emotional Learning, Dual Language Learning, and Early Intervention. To gain a better understanding of teacher and administrator perspectives on these core principles of early childhood education, a comprehensive survey was administered online, with a total of # teacher and # administrator respondents. Results indicate that TK and Kindergarten teachers are fairly knowledgeable and confident with these four core principles of early learning and instruction, but administrators report varied levels of appreciation for Developmentally Appropriate Practice and Play-Based Instruction in the context of their work. It appears that teachers' educational background and experience may influence their perspectives, pointing to specific recommendations for professional development opportunities. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]