The effects of brain injury acquired early in life on the development of cognition and behavior are not well understood. Deciphering these effects and modeling their neurodevelopmental trajectories are major concerns for clinicians and scientists. Historically, a prevailing notion has been that early-onset brain damage has a more favorable prognosis than does brain damage acquired in adulthood. However, there is growing evidence suggesting that early-onset damage to prefrontal brain structures may have devastating consequences on the emergence of adaptive behavior throughout development. Particularly prominent are disorders of personality, social behavior, and executive functions such as planning and decision making. This special issue presents a series of new empirical studies that address these issues in depth, from several different perspectives, and in both human and animal participants. The findings promise to shed further light on both the neurobiology of development, and diverse neurodevelopmental disorders. Such advances may also enhance clinical diagnosis and facilitate the design of more effective interventions to help reduce the tremendous burden that neurodevelopmental disorders place on personal well-being, family structure, educational systems, and social resources.