Dawn P. Flanagan, PhD, is Professor of Psychology and Director of the School of Psychology Training Programs at St. John's University in Jamaica, NY, and Clinical Assistant Professor at the Yale Child Study Center. She is the author or coauthor of several popular books in the Essentials series, including Essentials of WJ III Cognitive Abilities Assessment and Essentials of Cross-Battery Assessment. Alan S. Kaufman, PhD, is Professor of Psychology at Yale University's Child Study Center in the School of Medicine and the Series Editor with Nadeen L. Kaufman of Wiley's Essentials of Psychological Assessment series. Dr. Kaufman worked closely with David Wechsler in the development and standardization of the WISC(R)-R, an earlier version of the test; has written numerous books on the Wechsler Scales and intelligence testing; and is the author of several popular assessment instruments used worldwide.