This guide provides conceptual as well as practical information for meeting the needs of all learners in heterogeneous classrooms. The first six sections discuss the growing heterogeneity in today's classrooms, the rationale for differentiated teaching and learning, the changing roles of teachers and students, the importance of creating classroom communities that nurture diversity, helpful ideas for organizing a classroom in which differentiated teaching and learning is practiced, and a step-by-step process for differentiation. The seventh section provides many examples of how to differentiate teaching and learning in four areas: (1) what students learn; (2) how students learn; (3) how students integrate and demonstrate what they have learned; and (4) how students and teachers utilize assessment throughout the learning process. Sections 8 and 9 include an in-depth look at actual classrooms through case studies. The first case study describes how two multi-age elementary classrooms utilize an integrated service delivery model between general and special education to differentiate teaching and learning for math and language. The second case study describes how high school students in one urban high school learn to become effective self-advocates. Appendices include a humor unit, a "camping" math unit, and a list of resources. (Contains 35 references.) (CR)