Developmental changes in cognitive abilities in childhood have long been of interest to researchers across many fields, including behavioral sciences, communications, education, and medicine. With the publication of research findings showing individual differences in the development of children”s learning skills has come the realization that models, methodologies, and analysis approaches that include consideration of individual differences are needed. It has brought an increase in research collaborations among experts in different fields who bring different approaches together in studies of cognitive abilities. This work has yielded a growing body of knowledge about how children with normal abilities and those with developmental disorders learn, gain skills in social competency, develop decision making and planning abilities, and acquire language skills and the skills needed for reading and writing. More recently, researchers have sought to use this body of knowledge as a basis for the early identification of children at risk for cognitive delays and for the development and evaluation of intervention approaches. The chapters in this book review literature in five areas of cognition, and provide theory- and research-based information on the applications of research findings and intervention approaches. Throughout the chapters, information on the interactions of different cognitive abilities and the role of individual differences in development that influences development assessments is included.