Developmental Psychopathology is a framework of both theoretical and methodological guidelines for the study of development processes that are at risk of problematic outcome due to disorder, high risk environment, or deleterious experiential history. The essential premise is that the sciences of typical and atypical development are mutually informative: Information from typical development provides the basis for understanding the norms of rates, sequences, and structures in relation to developmental risk, delay, and impairment. Conversely, information from atypical populations is informative about the extent to which the laws and principles derived from typical situations are maintained universally, even in extreme cases. This framework allows researchers to consider developmental phenomena that are unique to a specific group and those that are more common within universal developmental principles.