How can today's teachers, whose classrooms are more culturally and linguistically diverse than ever before, ensure that their students achieve at high levels? How can they design units and lessons that support English learners in language development and content learning—simultaneously? Authors Amy Heineke and Jay McTighe provide the answers by adding a lens on language to the widely used Understanding by Design® framework (UbD® framework) for curriculum design, which emphasizes teaching for understanding, not rote memorization. Readers will learn the components of the UbD framework; the fundamentals of language and language development; how to use diversity as a valuable resource for instruction by gathering information about students’ background knowledge from home, community, and school; how to design units and lessons that integrate language development with content learning in the form of essential knowledge and skills; and how to assess in ways that enable language learners to reveal their academic knowledge. Student profiles, real-life classroom scenarios, and sample units and lessons provide compelling examples of how teachers in all grade levels and content areas use the UbD framework in their culturally and linguistically diverse classrooms. Combining these practical examples with findings from an extensive research base, the authors deliver a useful and authoritative guide for reaching the overarching goal: ensuring that all students have equitable access to high-quality curriculum and instruction.