The objective of this book is to make its readers better informed and more critical consumers of clinical research to help them recognize the strengths and the weaknesses of scientific publications. In doing so, the reader will be able to distinguish patient-important and methodologically sound studies from those having limitations in design, conduct and interpretation. There are no prerequisites for reading this book. The text is basic and has no statistical formulas. Key take-home messages are listed at the end of each chapter. The large number of cartoons has two purposes: First, to make the text easier to read and generate a few laughs and, second, to underscore specific points, sometimes in a provocative way. Bengt D. Furberg, MD, PhD is board-certified in internal medicine. After spending a decade as medical director in the pharmaceutical industry, he now serves as medical consultant, evaluating the safety and efficacy of pharmaceutical products and medical devices and promoting evidence-based medicine. His brother, Curt D. Furberg, MD, PhD, is Professor in the Division of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, NC, USA. After arriving in the United States from Sweden, he worked at the National Heart, Lung, and Blood Institute of the National Institutes of Health for 12 years. He is co-author of Fundamentals of Clinical Trials with Lawrence M. Friedman and David L. DeMets. His areas of interest are clinical trials, evidence-based medicine and drug safety. The authors have acquired much of their knowledge about clinical studies through the "trial and error" method. Thus, they have personal experience with many of the problems they describe.