Yuelin Li is a research psychologist and a behavioral statistician. His appointment at Memorial Sloan-Kettering Cancer Center allows him to apply a range of statistical techniques in understanding complex human behaviors---social network influence of young adult smoking, genetic-environment interaction in cognitive impairment, health behavior change, psychosocial and quality of life outcomes in cancer treatment, survivorship, and end of life care.Jonathan Baron is Professor of Psychology at the University of Pennsylvania, where he teaches Judgments and Decision and does research people's judgments and decisions about public policies. He has been fascinated by the promise of computers since about 1960 and has come of age with them and used them in his research. In 2000, he began the Web site (http://finzi.psych.upenn.edu) and document that led to this book, which was then mostly about data layout, until Yuelin Li (who shared the same PhD advisor, David Krantz) volunteered to help with the more substantive parts. Baron is founding and current editor of the journal Judgment and Decision Making.