This monograph presents the pediatric portion of the NationalInstitutes of Health (NIH) Toolbox Cognition Battery (CB) of theNIH Toolbox for the Assessment of Neurological and BehavioralFunction. The NIH Toolbox is an initiative of the NeuroscienceBlueprint, a collaborative framework through which 16 NIHInstitutes, Centers, and Offi ces jointly supportneuroscience-related research, to accelerate discoveries and reducethe burden of nervous system disorders. The CB is one of fourmodules that measure cognitive, emotional, sensory, and motorhealth across the lifespan. The CB is unique in its continuity acrosschildhood, adolescence, early adulthood, and old age, and in orderto help create a common currency among disparate studies, it isalso available at low cost to researchers for use in large-scalelongitudinal and epidemiologic studies. Chapter 1 describes theevolution of the CB; methods for selecting cognitive subdomains andinstruments; the rationale for test design; and a validation studyin children and adolescents, ages 3 to 15 years. Subsequentchapters feature detailed discussions of each test measure and its psychometric properties (Chapters2-6), the factor structure of the test battery (Chapter 7), the effects of age and education on composite test scores (Chapter8), and a final summary and discussion (Chapter 9). As the chaptersin this monograph demonstrate, the CB has excellent psychometricproperties, and the validation study provided evidence for theincreasing differentiation of cognitive abilities with age.