This book focuses on the clinical and preclinical research on traumatic brain injuries where age at time of injury (young versus aged) reveals both parallel and divergent findings at the molecular, cellular, and behavioral levels with insights into alterations in brain structure and function and the implications for recovery. The authors address the hurdles that have been overcome, consider new directions inspired by the most recent research, and the value of data sharing and evidenced based-practice. Traumatic Brain Injuries: Tackling the Unique Terrain of the Injured Young and Aged Brain explores the challenges imposed by an injury that not only causes tissue damage but disrupts brain development and may incite pathological events in the aging brain. With the proliferation of the research literature in traumatic brain injuries, this is the time for a book that surveys the landscape and assesses where the field is headed and what is needed moving forward.