This brief identifies important elements of high-quality early childhood education programs as indicated by research and professional standards. These include: - Early learning standards and curricula that address the whole child, are developmentally appropriate, and are effectively implemented. - Assessments that consider children's academic, social-emotional, and physical progress and contribute to instructional and program planning. - Well-prepared teachers who provide engaging interactions and classroom environments that support learning. - Ongoing support for teachers, including coaching and mentoring. - Support for English learners and students with special needs. - Meaningful family engagement. - Sufficient learning time. - Small class sizes with low student-teacher ratios. - Program assessments that measure structural quality and classroom interactions. - A well-implemented state quality rating and improvement system. These high-quality building blocks should be the foundation of any early childhood education system. (author abstract)