This document discusses universal design for learning (UDL) and the central role of technology in implementing UDL principles. UDL is a framework that aims to provide flexible learning environments and materials to support all students. It identifies three principles - representation, action and expression, and engagement. The document also notes that recent brain research shows individuals process information differently and technology allows for personalized instruction to support learner diversity. Tools on the CAST website like the UDL Solutions Finder and Lesson Builder help apply UDL principles.