For decades, the American Cancer Society and others have relentlessly campaigned for early cancer detection. And the campaign has been successful - the Journal of the American Medical Association recently reported that only 2% of Americans felt that there are too many cancer-screening tests. Despite this enthusiasm, expert panels of physicians and scientists, after careful reviews of the evidence, do not always endorse screening. Facing these conflicts can be distressing, particularly when confronting issues as serious as cancer. This book offers insights that clarify the issues for patients and physicians alike. As the subtitle suggests, Welch is skeptical about screening, and his text challenges the establishment. However, Welch is not a medical outsider. He is a practicing physician, a Professor at the Dartmouth Medical School, the former editor of a medical journal, and a researcher who has helped reshape professional thinking in articles in the New England Journal of Medicine, Journal of the American Medical Association, Annals of Internal Medicine, and other key medical journals. Using the traditional medical literature, Welch raises some very challenging questions for anyone considering cancer screening. Welch's book provides the reader with a new way to think about testing. He tells how cancer tests may identify disease for which there is no effective treatment, or for which the consequences of treatment are worse than the consequences of the disease. Welch explains why it may sometimes be better not to know you have cancer. In fact, many of us have conditions that will never affect us. In one section, he uses data from the pathology literature to demonstrate how fuzzy the definition of early cancer realy is - that different pathologists can examine the same specimens and come to different conclusions about whether cancer is present. Another section offers easy rules that clarify misleading reports of cancer rates. By walking us through the meaning of cancer statistics for individual patients, Welch clarifies what numbers should be important to individual patients. The bottom line is that this book takes on a difficult topic with remarkable clarity. Dr. Welch provides tools that will help patients play a more active role in their own health care decision making. Robert M. Kaplan is Professor and Chair of the Department of Family and Preventive Medicine at the University of California, San Diego School of Medicine.