Studies have criticized age-graded schools as creating a barrier to meeting the goals of equity and instructional excellence in schools. This handbook provides research on multiage classroom practices and argues that a multiage system better addresses and meets students' needs. Information is presented on the following topics: educational reform, parental education, cooperation in implementation, class size, multiyear teaching, grouping for purpose, time challenges, thematic planning, multiple intelligences, music in the multiage classroom, physical education in the multiage classroom, art in the multiage classroom, student-directed learning, assessment, and several case studies of working multiage classrooms. A large section of the handbook contains profiles from 13 working multiage classroom schools. Sample information from these schools includes report cards, assessment tools, curriculum outlines, sample letters to parents, grant requests, and bibliographies. A glossary of multiage classroom terminology and a resource section of workshops, conferences, newsletters, and organizations are also included. Contains 178 references in the areas of multiage education materials, developmental education, cooperative learning, curriculum, learning centers, learning styles, multiple intelligences, and multiage educators. (SD)