Developmental disabilities can impose significant limitations on the lives of infants, children, youth, and their families. Understanding the processes that underlie disability and their effects on development informs theory and practice. Early intervention has the potential to produce positive outcomes for infants, young children, and their families. FPG investigators have established some of the central features of practice in early intervention, such as family-focused programming, early childhood inclusion, and response to intervention. FPG continues its commitment to identifying the features of disability that potentially impact development and the participation of individuals in society, establishing practices that are effective in promoting positive outcomes for children, and using this information to inform policy and practice.