By consolidating forty years of Zigler's research with the work of other major researchers in the field of personality, this book provides a single resource for students, researchers, and professionals working in the field of mental retardation. The basic focus is that although cognitive impairment is a defining feature, personality, emotions, and motivation play a significant role in the behavior of individuals with mental retardation. The comprehensive overview of the theory, research, and practical considerations provided in this book has relevance in identifying, educating, and integrating mentally retarded individuals into society.