Behavioural medicine has matured as a field to the point where all recognize that different populations present different issues. Psychological reactions and patterns affect the health and well-being of children, as well as adults, and numerous standardized instruments for the assessment of a variety of areas of children’s functioning are currently available. Yet, it can be difficult for practitioners and researchers searching through general compendia of resources for child assessment to identify the optimal ones to meet their particular needs and to choose among them. This reference guide sorts, presents and reviews all the measures that can be used to evaluate the behavioural, cognitive and emotional aspects of children’s health. It organizes the measures under eight general headings, such as quality of life, adherence, pain management, and patient satisfaction. Each chapter begins with an overview of the underlying theoretical construct and any concerns about how to measure it. Descriptions and reviews of relevant instruments follow; these include information on administration, scoring, psychometric properties, and ordering, as well as comments by the instruments’ developers.