This resource book contains a variety of information on multiage practice, and instruction in mixed-age and grade-level classrooms. The first two parts of the book contain 24 reprinted articles: (1) "Ready To Learn: A Seven-Step Strategy"; (2) "On Tracking and Individual Differences: A Conversation with Jeannie Oakes"; (3) "Multiage Grouping"; (4) "Multiage Classrooms: Children Learning at Their Own Speed"; (5) "Multi-Age Programs in Primary Grades"; (6) "Multiage: Why It's Needed"; (7) "Questions and Answers about Multiage Programs"; (8) "The Whys and Hows of the Multi-Age Classroom"; (9) "Off the Track: Children Thrive in Ungraded Primary Schools"; (10) "Multi-Age Classrooms: Option to an Outdated System"; (11) "When Your Principal Asks: What Can I Expect To See in Multi-Age Classrooms?"; (12) "The Country School Comes to Town: A Case Study of Multiage Grouping and Teaching"; (13) "The Gift of Time"; (14) "Ungraded Primaries Begin To Take Over in Kentucky"; (15) "Warm Up to Cooperative Learning"; (16) "Putting Research to Work: Cooperative Learning"; (17) "Enhancing Success in Heterogeneous Classrooms and Schools"; (18) "Questions about Implementing Mixed-Age Grouping"; (19) "A Review of the Quantitative Research on Multigrade Instruction"; (20) "A Review of the Qualitative Research on Multigrade Instruction"; (21) "On the Merits of Multiage Classrooms"; (22) "Ungraded Classrooms: Fail-Safe Schools?"; (23) "Teaching Combined Grade Classes: Real Problems and Promising Practices"; and (24) "Nongraded Primary Instruction." The third part of the book contains a 42-item bibliography. Eleven models of multiage practice are profiled in the fourth part. The last part of the book contains information and strategies to help educators create multiage programs. (TJQ)