The concept of Universal Design for Learning (UDL) emerged from universal design in architecture. UDL aims to expand learning opportunities for all learners through providing multiple means of representation, expression, and engagement. It was developed by the Center for Applied Special Technology (CAST) based on research showing how the brain's recognition, strategic, and affective networks process information. UDL calls for flexible curriculum and instructional methods that accommodate diverse learners. Teachers can apply UDL principles by knowing their students, communicating, planning for all learners, and using appropriate technologies.