Norm O' Rourke,?Ph.D., R. Psych., is a clinical psychologist and assistant professor in the Department of Geontology at Simon Fraser University in Vancouver, Bristish Columbia, and an associate member of the SFU Department of Psychology. Dr. O'Rourke's areas of research interest include mental illness and well-being, marriage in later life, and test construction and validation. He has lived and worked in Canada, the United States, Europe, and Israel. Larry Hatcher, Ph.D., is a professor of psychology at Saginaw Valley State University in Saginaw, Michigan, where he teaches courses in general psychology, industrial psychology, statistics, and computer applications in data analysis. The author of several books dealing with statistics and data analysis, Dr. Hatcher has taught at the college level since 1984, after earning his doctorate in industrial and organizational psychology from Bowling Green State University. Edward J. Stepanski, Ph.D., is the director of the Sleep Disorders Service and Research Center at Rush University Medical Center in Chicago and as associate professor of psychology and medicine at Rush Medical College. He uses data warehousing and computer analysis for a variety of research projects aimed at understanding sleep disorders and quantifying sleep-related daytime impairment. Dr. Stepanski earned his doctorate in clinical psychology from Bowling Green State University in 1985 and has written more than 50 papers and book chapters on sleep disorders medicine.