David G. Kleinbaum is a Professor of Epidemiology at Emory University's Rollins School of Public Health in Atlanta, GA, and an internationally recognized expert in teaching biostatistical and epidemiological concepts and methods at all levels. He is the author or co-author of several widely acclaimed textbooks including ActivEpi CD ROM, The ActivEpi Companion Textbook, Applied Regression Analysis and Other Multivariable Methods, Epidemiologic Research: Principles and Quantitative Methods, Logistic Regression-A Self-Learning Text, and Survival Analysis-A Self-Learning Text. Dr. Kleinbaum has more than 25 years of experience teaching over 100 short courses on statistical and epidemiologic methods to a variety of international audiences, and has published widely in both the methodological and applied public health literature. He is also an experienced and sought-after consultant, and is presently an ad-hoc consultant to research staff at the Centers for Disease Control and Prevention. In December 2005, Dr. Kleinbaum was the first recipient of the Association of Schools of Public Health Pfizer Award for Career Teaching Excellence. In November 2006, he also received the American Public Health Association's 2006 award for Career Teaching Excellence in Epidemiology. Dr. Kevin M. Sullivan is an Associate Professor of Epidemiology at Emory University's Rollins School of Public Health. He has worked in the area of epidemiology and public health for over 30 years and has over 80 publications in peer-reviewed journals and has published chapters in several books. He is one of the developers of Epi Info, a freely downloadable web-based software package for the analysis of epidemiologic data published by the Centers for Disease Control and Prevention. He is also the co-author of OpenEpi, a freely downloadable web-based calculator for epidemiologic data (www.OpenEpi.com). Ms. Nancy Barker is a statistical consultant who formerly worked at the Centers for Disease Control and Prevention. She is an Instructor in the Career MPH at the Rollins School of Public Health at Emory University where she teaches a distance learning course on basic epidemiology that uses ActivEpi CD and ActivEpi Companion Text as the course textbooks.