Special education is now an established part of public education in the United States ' by law and by custom. However, it is still widely misunderstood and continues to be dogged by controversies related to such things as categorization, grouping, assessment, placement, funding, instruction, and a variety of legal issues. The purpose of this thirteen-part, fifty-nine chapter Handbook is to help profile and bring greater clarity to this sprawling and growing field. To insure consistency across the volume, chapter authors review and integrate existing research, identify strengths and weaknesses, note gaps in the literature, and discuss implications for practice and future research. Comprehensive ' fifty-nine chapters cover all aspects of special education in the United States including cultural and international comparisons. Issues and Trends ' in addition to synthesizing empirical findings and providing a critical analysis of the status and direction of current research, chapter authors discuss issues related to practice and reflect on trends in thinking. Categorical Chapters ' in order to provide a comprehensive and comparative treatment of the twelve categorical chapters in section IV, chapter authors follow a consistent outline: Definition, Causal Factors, Identification, Behavioral Characteristics, Assessment, Educational Programming, and Trends and Issues. Expertise ' edited by two of the most accomplished scholars in special education, chapter authors include a mixture of established and rising young stars in the field.