Robert R. McCrae, PhD, is Research Psychologist at the Gerontology Research Center of the National Institute on Aging. He received his doctorate in personality psychology from Boston University in 1976, and has since conducted research on personality structure, assessment, and development. His recent work has centered on cross-cultural studies of personality. He has authored or coauthored over 250 articles and chapters, and with Paul T. Costa, Jr., he is author of the Revised NEO Personality Inventory. Note: Personality in Adulthood, Second Edition, was written by Robert R. McCrae and Paul T. Costa, Jr., in their private capacities. No official support or endorsement by the National Institute on Aging is intended or should be inferred.

Paul T. Costa, Jr., PhD, is Chief of the Laboratory of Personality and Cognition at the National Institute on Aging's Intramural Research Program in Baltimore, Maryland. His enduring interests are in the structure and measurement of personality and in lifespan development, psychopathology, and neurobiological bases of personality. He has authored or coauthored over 300 papers and chapters and has served as President of APA Divisions 5 and 20, the Association for Research in Personality, and the International Society for the Study of Individual Differences. Note: Personality in Adulthood, Second Edition, was written by Robert R. McCrae and Paul T. Costa, Jr., in their private capacities. No official support or endorsement by the National Institute on Aging is intended or should be inferred.