Comprehensive school reform involves changes in every aspect of school operations, from classroom instruction to school governance. Some schools develop their own reform approach from within. Others seek assistance from without, particularly from organizations that have developed coherent, research-based approaches, or school-reform models. For such schools, selecting the right reform model is crucial. This catalog describes 48 school-reform models. Its purpose is to aid schools, school districts, and states as they investigate external models that can be incorporated into comprehensive school-reform programs. The catalog divides these models into several categories: entire-school models, reading/language models, mathematics models, science models, and other models, which can be used as building blocks for comprehensive reform. It contains introductory information on 27 entire-school models and 21 skill- and content-based models. Each entry analyzes the model's general approach, student results, implementation assistance, and costs, among other elements. Criteria for selecting models include evidence of effectiveness in improving student academic achievement, extent of replication, implementation assistance provided to schools, and comprehensiveness. Each description lists the model's origin or scope, a general description, results, implementation plan, costs, student populations, special considerations, selected evaluations, sample sites, contact information, and state standards and accountability. (RT)