Critically examining the case for and against screening people for early detection of cancer, this book reviews research-based knowledge on the value of early diagnosis for several different cancers ranging from neuroblastoma in infants to prostate cancer in old age. For each cancer site, the natural history of disease progression is reviewed and how the course may be altered by early intervention. Available screening tests are assessed both for their potential benefit and disadvantage. The information presented in this thoughtful review will assist health policy-makers to make decisions on cancer screening. Clinical researchers considering setting up screening studies will be made aware of the pitfalls of evaluation; practitioners and postgraduate students will find a readable introduction to the subject.