In this issue of Pediatric Clinics of North America, guest editors Drs. Roger W. Apple and Ethel G. Clemente bring their considerable expertise to the topic of Role of Psychologists in Pediatric Subspecialties. Top experts in the field highlight the interdisciplinary nature of primary care of children where psychology is a factor, placing emphasis the clinical topics, disease states, or medical specialties where mental health has a significant impact on the outcome and successful treatment of clinical issues in children. This issue offers a unique focus on collaboration between the psychologist and pediatrician to optimize outcomes.