Teachers struggle every day to bring quality instruction to their students. Beset by lists of content standards and accompanying ''high-stakes'' accountability tests, many educators sense that both teaching and learning have been redirected in ways that are potentially impoverishing for those who teach and those who learn.

Educators need a model that acknowledges the centrality of standards but also ensures that students truly understand content and can apply it in meaningful ways. For many educators, Understanding by Design addresses that need.Simultaneously, teachers find it increasingly difficult to ignore the diversity of the learners who populate their classrooms. Few teachers find their work effective or satisfying when they simply ''serve up'' a curriculum--even an elegant one--to students with no regard for their varied learning needs.